Convert.ToInt16 方法

public:
 static short ToInt16(System::String ^ value, int fromBase);

public static short ToInt16 (string value, int fromBase);

static member ToInt16 : string * int -> int16

Public Shared Function ToInt16 (value As String, fromBase As Integer) As Short

参数

返回

Int16

一个与 value 中数字等效的 16 位带符号整数，如果 value 为 null，则为 0（零）。A 16-bit signed integer that is equivalent to the number in value, or 0 (zero) if value is null.

例外

示例

下面的示例尝试将字符串数组中的每个元素解释为十六进制字符串，并将其转换为16位带符号整数。The following example attempts to interpret each element in a string array as a hexadecimal string and to convert it to a 16-bit signed integer.

using System;

public class Example
{
   public static void Main()
   {
      string[] hexStrings = { "8000", "0FFF", "f000", "00A30", "D", "-13",
                              "9AC61", "GAD" };
      foreach (string hexString in hexStrings)
      {
         try {
            short number = Convert.ToInt16(hexString, 16);
            Console.WriteLine("Converted '{0}' to {1:N0}.", hexString, number);
         }
         catch (FormatException) {
            Console.WriteLine("'{0}' is not in the correct format for a hexadecimal number.",
                              hexString);
         }
         catch (OverflowException) {
            Console.WriteLine("'{0}' is outside the range of an Int16.", hexString);
         }
         catch (ArgumentException) {
            Console.WriteLine("'{0}' is invalid in base 16.", hexString);
         }
      }
   }
}
// The example displays the following output:
//       Converted '8000' to -32,768.
//       Converted '0FFF' to 4,095.
//       Converted 'f000' to -4,096.
//       Converted '00A30' to 2,608.
//       Converted 'D' to 13.
//       '-13' is invalid in base 16.
//       '9AC61' is outside the range of an Int16.
//       'GAD' is not in the correct format for a hexadecimal number.

Module Example
   Public Sub Main()
      Dim hexStrings() As String = { "8000", "0FFF", "f000", "00A30", "D", _
                                     "-13", "9AC61", "GAD" }
      For Each hexString As String In hexStrings
         Try
            Dim number As Short = Convert.ToInt16(hexString, 16)
            Console.WriteLine("Converted '{0}' to {1:N0}.", hexString, number)
         Catch e As FormatException
            Console.WriteLine("'{0}' is not in the correct format for a hexadecimal number.", _
                              hexString)
         Catch e As OverflowException
            Console.WriteLine("'{0}' is outside the range of an Int16.", hexString)
         Catch e As ArgumentException
            Console.WriteLine("'{0}' is invalid in base 16.", hexString)
         End Try
      Next                                            
   End Sub
End Module
' The example displays the following output:
'       Converted '8000' to -32,768.
'       Converted '0FFF' to 4,095.
'       Converted 'f000' to -4,096.
'       Converted '00A30' to 2,608.
'       Converted 'D' to 13.
'       '-13' is invalid in base 16.
'       '9AC61' is outside the range of an Int16.
'       'GAD' is not in the correct format for a hexadecimal number.

注解

如果 fromBase 为16，则可以为参数指定的数字加上 value "0x" 或 "0x" 作为前缀。If fromBase is 16, you can prefix the number specified by the value parameter with "0x" or "0X".

由于非基数10数值表示形式不支持负号，因此该 ToInt16(String, Int32) 方法假设负数使用两个的补码表示形式。Because the negative sign is not supported for non-base 10 numeric representations, the ToInt16(String, Int32) method assumes that negative numbers use two's complement representation. 换言之，该方法始终将整数 (位 15) 的最高顺序二进制位解释为其符号位。In other words, the method always interprets the highest-order binary bit of an integer (bit 15) as its sign bit. 因此，可以编写代码，在此代码中，在 Int16 Int16 不引发异常的情况下，将不在数据类型范围内的非 base 10 数字转换为值。As a result, it is possible to write code in which a non-base 10 number that is out of the range of the Int16 data type is converted to an Int16 value without the method throwing an exception. 下面的示例 Int16.MaxValue 按1递增，将得到的数字转换为其十六进制字符串表示形式，然后调用 ToInt16(String, Int32) 方法。The following example increments Int16.MaxValue by one, converts the resulting number to its hexadecimal string representation, and then calls the ToInt16(String, Int32) method. 方法不会引发异常，而是显示消息 "0x8000 转换为-32768"。Instead of throwing an exception, the method displays the message, "0x8000 converts to -32768."

// Create a hexadecimal value out of range of the Int16 type.
string value = Convert.ToString((int) short.MaxValue + 1, 16);
// Convert it back to a number.
try
{
   short number = Convert.ToInt16(value, 16);
   Console.WriteLine("0x{0} converts to {1}.", value, number);
}
catch (OverflowException)
{
   Console.WriteLine("Unable to convert '0x{0}' to a 16-bit integer.", value);
}

' Create a hexadecimal value out of range of the Int16 type.
Dim value As String = Convert.ToString(CInt(Short.MaxValue) + 1, 16)
' Convert it back to a number.
Try
   Dim number As Short = Convert.ToInt16(value, 16)
   Console.WriteLine("0x{0} converts to {1}.", value, number)
Catch e As OverflowException
   Console.WriteLine("Unable to convert '0x{0}' to a 16-bit integer.", value)
End Try   

执行二元运算或数值转换时，开发人员始终负责验证方法是否使用适当的数值表示形式来解释特定值。When performing binary operations or numeric conversions, it is always the responsibility of the developer to verify that a method is using the appropriate numeric representation to interpret a particular value. 如下面的示例所示，通过先检索数值的符号，然后将其转换为十六进制字符串表示形式，可以确保方法适当地处理溢出。As the following example illustrates, you can ensure that the method handles overflows appropriately by first retrieving the sign of the numeric value before converting it to its hexadecimal string representation. 如果原始值为正值，但转换回整数产生负值，则引发异常。Throw an exception if the original value was positive but the conversion back to an integer yields a negative value.

// Create a hexadecimal value out of range of the Short type.
int sourceNumber = (int) short.MaxValue + 1;
bool isNegative = (Math.Sign(sourceNumber) == -1);
string value = Convert.ToString(sourceNumber, 16);
short targetNumber;
try
{
   targetNumber = Convert.ToInt16(value, 16);
   if (! isNegative && ((targetNumber & 0x8000) != 0))
      throw new OverflowException();
   else
      Console.WriteLine("0x{0} converts to {1}.", value, targetNumber);
}
catch (OverflowException)
{
   Console.WriteLine("Unable to convert '0x{0}' to a 16-bit integer.", value);
}
// Displays the following to the console:
//    Unable to convert '0x8000' to a 16-bit integer.

' Create a hexadecimal value out of range of the Short type.
Dim sourceNumber As Integer = CInt(Short.MaxValue) + 1
Dim isNegative As Boolean = (Math.Sign(sourceNumber) = -1)
Dim value As String = Convert.ToString(sourceNumber, 16)
Dim targetNumber As Short
Try
   targetNumber = Convert.ToInt16(value, 16)
   If Not isNegative And ((targetNumber And &H8000) <> 0) Then
      Throw New OverflowException()
   Else 
      Console.WriteLine("0x{0} converts to {1}.", value, targetNumber)
   End If    
Catch e As OverflowException
   Console.WriteLine("Unable to convert '0x{0}' to a 16-bit integer.", value)
End Try 
' Displays the following to the console:
'    Unable to convert '0x8000' to a 16-bit integer.     

public:
 static short ToInt16(System::String ^ value, IFormatProvider ^ provider);

public static short ToInt16 (string value, IFormatProvider provider);

static member ToInt16 : string * IFormatProvider -> int16

Public Shared Function ToInt16 (value As String, provider As IFormatProvider) As Short

参数

返回

Int16

一个与 value 中数字等效的 16 位带符号整数，如果 value 为 null，则为 0（零）。A 16-bit signed integer that is equivalent to the number in value, or 0 (zero) if value is null.

例外

示例

下面的示例使用对象通过方法转换16位整数的字符串表示形式 ToInt16 IFormatProvider 。The following example converts string representations of 16-bit integers with the ToInt16 method, using an IFormatProvider object.

// Example of the Convert::ToInt16( String* ) and 
// Convert::ToInt16( String*, IFormatProvider* ) methods.
using namespace System;
using namespace System::Globalization;
const __wchar_t * protoFmt = L"{0,-20}{1,-20}{2}";

// Get the exception type name; remove the namespace prefix.
String^ GetExceptionType( Exception^ ex )
{
   String^ exceptionType = ex->GetType()->ToString();
   return exceptionType->Substring( exceptionType->LastIndexOf( '.' ) + 1 );
}

void ConvertToInt16( String^ numericStr, IFormatProvider^ provider )
{
   Object^ defaultValue;
   Object^ providerValue;
   
   // Convert numericStr to Int16 without a format provider.
   try
   {
      defaultValue = Convert::ToInt16( numericStr );
   }
   catch ( Exception^ ex ) 
   {
      defaultValue = GetExceptionType( ex );
   }

   
   // Convert numericStr to Int16 with a format provider.
   try
   {
      providerValue = Convert::ToInt16( numericStr, provider );
   }
   catch ( Exception^ ex ) 
   {
      providerValue = GetExceptionType( ex );
   }

   Console::WriteLine( gcnew String( protoFmt ), numericStr, defaultValue, providerValue );
}

int main()
{
   
   // Create a NumberFormatInfo object and set several of its
   // properties that apply to numbers.
   NumberFormatInfo^ provider = gcnew NumberFormatInfo;
   
   // These properties affect the conversion.
   provider->NegativeSign = "neg ";
   provider->PositiveSign = "pos ";
   
   // These properties do not affect the conversion.
   // The input string cannot have decimal and group separators.
   provider->NumberDecimalSeparator = ".";
   provider->NumberGroupSeparator = ",";
   array<Int32>^sizes = {3};
   provider->NumberGroupSizes = sizes;
   provider->NumberNegativePattern = 0;
   Console::WriteLine( "This example of\n"
   "  Convert::ToInt16( String* ) and \n"
   "  Convert::ToInt16( String*, IFormatProvider* ) "
   "\ngenerates the following output. It converts "
   "several strings to \nshort values, using "
   "default formatting or a NumberFormatInfo object.\n" );
   Console::WriteLine( gcnew String( protoFmt ), "String to convert", "Default/exception", "Provider/exception" );
   Console::WriteLine( gcnew String( protoFmt ), "-----------------", "-----------------", "------------------" );
   
   // Convert strings, with and without an IFormatProvider.
   ConvertToInt16( "12345", provider );
   ConvertToInt16( "+12345", provider );
   ConvertToInt16( "pos 12345", provider );
   ConvertToInt16( "-12345", provider );
   ConvertToInt16( "neg 12345", provider );
   ConvertToInt16( "12345.", provider );
   ConvertToInt16( "12,345", provider );
   ConvertToInt16( "(12345)", provider );
   ConvertToInt16( "32768", provider );
   ConvertToInt16( "-32769", provider );
}

/*
This example of
  Convert::ToInt16( String* ) and
  Convert::ToInt16( String*, IFormatProvider* )
generates the following output. It converts several strings to
short values, using default formatting or a NumberFormatInfo object.

String to convert   Default/exception   Provider/exception
-----------------   -----------------   ------------------
12345               12345               12345
+12345              12345               FormatException
pos 12345           FormatException     12345
-12345              -12345              FormatException
neg 12345           FormatException     -12345
12345.              FormatException     FormatException
12,345              FormatException     FormatException
(12345)             FormatException     FormatException
32768               OverflowException   OverflowException
-32769              OverflowException   FormatException
*/

// Example of the Convert.ToInt16( string ) and
// Convert.ToInt16( string, IFormatProvider ) methods.
using System;
using System.Globalization;

class ToInt16ProviderDemo
{
    static string format = "{0,-20}{1,-20}{2}";

     // Get the exception type name; remove the namespace prefix.
    static string GetExceptionType( Exception ex )
    {
        string exceptionType = ex.GetType( ).ToString( );
        return exceptionType.Substring(
            exceptionType.LastIndexOf( '.' ) + 1 );
    }

    static void ConvertToInt16( string numericStr,
        IFormatProvider provider )
    {
        object defaultValue;
        object providerValue;

        // Convert numericStr to Int16 without a format provider.
        try
        {
            defaultValue = Convert.ToInt16( numericStr );
        }
        catch( Exception ex )
        {
            defaultValue = GetExceptionType( ex );
        }

        // Convert numericStr to Int16 with a format provider.
        try
        {
            providerValue = Convert.ToInt16( numericStr, provider );
        }
        catch( Exception ex )
        {
            providerValue = GetExceptionType( ex );
        }

        Console.WriteLine( format, numericStr,
            defaultValue, providerValue );
    }

    public static void Main( )
    {
        // Create a NumberFormatInfo object and set several of its
        // properties that apply to numbers.
        NumberFormatInfo provider = new NumberFormatInfo();

        // These properties affect the conversion.
        provider.NegativeSign = "neg ";
        provider.PositiveSign = "pos ";

        // These properties do not affect the conversion.
        // The input string cannot have decimal and group separators.
        provider.NumberDecimalSeparator = ".";
        provider.NumberGroupSeparator = ",";
        provider.NumberGroupSizes = new int[ ] { 3 };
        provider.NumberNegativePattern = 0;

        Console.WriteLine("This example of\n" +
            "  Convert.ToInt16( string ) and \n" +
            "  Convert.ToInt16( string, IFormatProvider ) " +
            "\ngenerates the following output. It converts " +
            "several strings to \nshort values, using " +
            "default formatting or a NumberFormatInfo object.\n" );
        Console.WriteLine( format, "String to convert",
            "Default/exception", "Provider/exception" );
        Console.WriteLine( format, "-----------------",
            "-----------------", "------------------" );

        // Convert strings, with and without an IFormatProvider.
        ConvertToInt16( "12345", provider );
        ConvertToInt16( "+12345", provider );
        ConvertToInt16( "pos 12345", provider );
        ConvertToInt16( "-12345", provider );
        ConvertToInt16( "neg 12345", provider );
        ConvertToInt16( "12345.", provider );
        ConvertToInt16( "12,345", provider );
        ConvertToInt16( "(12345)", provider );
        ConvertToInt16( "32768", provider );
        ConvertToInt16( "-32769", provider );
    }
}

/*
This example of
  Convert.ToInt16( string ) and
  Convert.ToInt16( string, IFormatProvider )
generates the following output. It converts several strings to
short values, using default formatting or a NumberFormatInfo object.

String to convert   Default/exception   Provider/exception
-----------------   -----------------   ------------------
12345               12345               12345
+12345              12345               FormatException
pos 12345           FormatException     12345
-12345              -12345              FormatException
neg 12345           FormatException     -12345
12345.              FormatException     FormatException
12,345              FormatException     FormatException
(12345)             FormatException     FormatException
32768               OverflowException   OverflowException
-32769              OverflowException   FormatException
*/

' Example of the Convert.ToInt16( String ) and 
' Convert.ToInt16( String, IFormatProvider ) methods.
Imports System.Globalization

Module ToInt16ProviderDemo

    Dim format As String = "{0,-20}{1,-20}{2}"

    ' Get the exception type name; remove the namespace prefix.
    Function GetExceptionType( ex As Exception ) As String

        Dim exceptionType   As String = ex.GetType( ).ToString( )
        Return exceptionType.Substring( _
            exceptionType.LastIndexOf( "."c ) + 1 )
    End Function

    Sub ConvertToInt16( numericStr As String, _
        provider As IFormatProvider )

        Dim defaultValue    As Object
        Dim providerValue   As Object

        ' Convert numericStr to Int16 without a format provider.
        Try
            defaultValue = Convert.ToInt16( numericStr )
        Catch ex As Exception
            defaultValue = GetExceptionType( ex )
        End Try

        ' Convert numericStr to Int16 with a format provider.
        Try
            providerValue = Convert.ToInt16( numericStr, provider )
        Catch ex As Exception
            providerValue = GetExceptionType( ex )
        End Try

        Console.WriteLine( format, numericStr, _
            defaultValue, providerValue )
    End Sub

    Sub Main( )

        ' Create a NumberFormatInfo object and set several of its
        ' properties that apply to numbers.
        Dim provider  As NumberFormatInfo = new NumberFormatInfo( )

        ' These properties affect the conversion.
        provider.NegativeSign = "neg "
        provider.PositiveSign = "pos "

        ' These properties do not affect the conversion.
        ' The input string cannot have decimal and group separators.
        provider.NumberDecimalSeparator = "."
        provider.NumberGroupSeparator = ","
        provider.NumberGroupSizes = New Integer( ) { 3 }
        provider.NumberNegativePattern = 0

        Console.WriteLine( "This example of" & vbCrLf & _
            "  Convert.ToInt16( String ) and " & vbCrLf & _
            "  Convert.ToInt16( String, IFormatProvider ) " & _
            vbCrLf & "generates the following output. It " & _
            "converts several strings to " & vbCrLf & "Short " & _
            "values, using default formatting " & _
            "or a NumberFormatInfo object." & vbCrLf )
        Console.WriteLine( format, "String to convert", _
            "Default/exception", "Provider/exception" )
        Console.WriteLine( format, "-----------------", _
            "-----------------", "------------------" )

        ' Convert strings, with and without an IFormatProvider.
        ConvertToInt16( "12345", provider )
        ConvertToInt16( "+12345", provider )
        ConvertToInt16( "pos 12345", provider )
        ConvertToInt16( "-12345", provider )
        ConvertToInt16( "neg 12345", provider )
        ConvertToInt16( "12345.", provider )
        ConvertToInt16( "12,345", provider )
        ConvertToInt16( "(12345)", provider )
        ConvertToInt16( "32768", provider )
        ConvertToInt16( "-32769", provider )
    End Sub 
End Module 

' This example of
'   Convert.ToInt16( String ) and
'   Convert.ToInt16( String, IFormatProvider )
' generates the following output. It converts several strings to
' Short values, using default formatting or a NumberFormatInfo object.
' 
' String to convert   Default/exception   Provider/exception
' -----------------   -----------------   ------------------
' 12345               12345               12345
' +12345              12345               FormatException
' pos 12345           FormatException     12345
' -12345              -12345              FormatException
' neg 12345           FormatException     -12345
' 12345.              FormatException     FormatException
' 12,345              FormatException     FormatException
' (12345)             FormatException     FormatException
' 32768               OverflowException   OverflowException
' -32769              OverflowException   FormatException

注解

provider 是一个 IFormatProvider 获取对象的实例 NumberFormatInfo 。provider is an IFormatProvider instance that obtains a NumberFormatInfo object. NumberFormatInfo对象提供有关的格式的区域性特定信息 value 。The NumberFormatInfo object provides culture-specific information about the format of value. 如果 provider 为 null ，则 NumberFormatInfo 使用当前区域性的。If provider is null, the NumberFormatInfo for the current culture is used.

如果你不希望在转换失败时处理异常，则可以改为调用 Int16.TryParse 方法。If you prefer not to handle an exception if the conversion fails, you can call the Int16.TryParse method instead. 它将返回一个 Boolean 值，该值指示转换是成功还是失败。It returns a Boolean value that indicates whether the conversion succeeded or failed.

另请参阅

• Parse(String)

public:
 static short ToInt16(System::Object ^ value, IFormatProvider ^ provider);

public static short ToInt16 (object value, IFormatProvider provider);

static member ToInt16 : obj * IFormatProvider -> int16

Public Shared Function ToInt16 (value As Object, provider As IFormatProvider) As Short

参数

返回

Int16

一个与 value 等效的 16 位带符号整数，如果 value 为 null，则为零。A 16-bit signed integer that is equivalent to value, or zero if value is null.

例外

示例

下面的示例定义一个实现的类 IConvertible 和一个实现的类 IFormatProvider 。The following example defines a class that implements IConvertible and a class that implements IFormatProvider. 实现的类的对象 IConvertible 保存值的数组 Double 。Objects of the class that implements IConvertible hold an array of Double values. 将每个类的对象传递给 ToInt16 方法。An object of each class is passed to the ToInt16 method. 此方法 Double 使用实现的对象 IFormatProvider 来确定如何计算平均值，从而返回值数组的平均值。This method returns an average of the array of Double values, using the object that implements IFormatProvider to determine how to calculate the average.

using namespace System;
using namespace System::Collections;

// Define the types of averaging available in the class 
// implementing IConvertible.
public enum class AverageType : short
{
   None = 0,
   GeometricMean = 1,
   ArithmeticMean = 2,
   Median = 3
};


// Pass an instance of this class to methods that require an 
// IFormatProvider. The class instance determines the type of 
// average to calculate.
ref class AverageInfo: public IFormatProvider
{
protected:
   AverageType AvgType;

public:

   // Specify the type of averaging in the constructor.
   AverageInfo( AverageType avgType )
   {
      this->AvgType = avgType;
   }


   // This method returns a reference to the containing object 
   // if an object of AverageInfo type is requested. 
   virtual Object^ GetFormat( Type^ argType )
   {
      if ( argType == AverageInfo::typeid)
            return this;
      else
            return (Object^)0;
   }


   property AverageType TypeOfAverage 
   {

      // Use this property to set or get the type of averaging.
      AverageType get()
      {
         return this->AvgType;
      }

      void set( AverageType value )
      {
         this->AvgType = value;
      }

   }

};


// This class encapsulates an array of double values and implements 
// the IConvertible interface. Most of the IConvertible methods 
// return an average of the array elements in one of three types: 
// arithmetic mean, geometric mean, or median. 
ref class DataSet: public IConvertible
{
private:
   static Object^ null = nullptr;

protected:
   ArrayList^ data;
   AverageInfo^ defaultProvider;

   // This method unboxes a boxed double.
   double UnBoxDouble( Object^ obj )
   {
      return  *static_cast<double^>(obj);
   }


public:

   // Construct the object and add an initial list of values.
   // Create a default format provider.
   DataSet( ... array<Double>^values )
   {
      data = gcnew ArrayList( (Array^)values );
      defaultProvider = gcnew AverageInfo( AverageType::ArithmeticMean );
   }


   // Add additional values with this method.
   int Add( double value )
   {
      data->Add( value );
      return data->Count;
   }


   property double Item[ int ]
   {

      // Get, set, and add values with this indexer property.
      double get( int index )
      {
         if ( index >= 0 && index < data->Count )
                  return UnBoxDouble( data[ index ] );
         else
                  throw gcnew InvalidOperationException( "[DataSet.get] Index out of range." );
      }

      void set( int index, double value )
      {
         if ( index >= 0 && index < data->Count )
                  data[ index ] = value;
         else
         if ( index == data->Count )
                  data->Add( value );
         else
                  throw gcnew InvalidOperationException( "[DataSet.set] Index out of range." );
      }

   }

   property int Count 
   {

      // This property returns the number of elements in the object.
      int get()
      {
         return data->Count;
      }

   }

protected:

   // This method calculates the average of the object's elements.
   double Average( AverageType avgType )
   {
      double SumProd;
      if ( data->Count == 0 )
            return 0.0;

      switch ( avgType )
      {
         case AverageType::GeometricMean:
            SumProd = 1.0;
            for ( int Index = 0; Index < data->Count; Index++ )
               SumProd *= UnBoxDouble( data[ Index ] );
            
            // This calculation will not fail with negative 
            // elements.
            return Math::Sign( SumProd ) * Math::Pow( Math::Abs( SumProd ), 1.0 / data->Count );

         case AverageType::ArithmeticMean:
            SumProd = 0.0;
            for ( int Index = 0; Index < data->Count; Index++ )
               SumProd += UnBoxDouble( data[ Index ] );
            return SumProd / data->Count;

         case AverageType::Median:
            if ( data->Count % 2 == 0 )
                        return (UnBoxDouble( data[ data->Count / 2 ] ) + UnBoxDouble( data[ data->Count / 2 - 1 ] )) / 2.0;
            else
                        return UnBoxDouble( data[ data->Count / 2 ] );

         default:
            return 0.0;
      }
   }


   // Get the AverageInfo object from the caller's format provider,
   // or use the local default.
   AverageInfo^ GetAverageInfo( IFormatProvider^ provider )
   {
      AverageInfo^ avgInfo = nullptr;
      if ( provider != nullptr )
            avgInfo = static_cast<AverageInfo^>(provider->GetFormat( AverageInfo::typeid ));

      if ( avgInfo == nullptr )
            return defaultProvider;
      else
            return avgInfo;
   }


   // Calculate the average and limit the range.
   double CalcNLimitAverage( double min, double max, IFormatProvider^ provider )
   {
      
      // Get the format provider and calculate the average.
      AverageInfo^ avgInfo = GetAverageInfo( provider );
      double avg = Average( avgInfo->TypeOfAverage );
      
      // Limit the range, based on the minimum and maximum values 
      // for the type.
      return avg > max ? max : avg < min ? min : avg;
   }


public:

   // The following elements are required by IConvertible.
   // None of these conversion functions throw exceptions. When
   // the data is out of range for the type, the appropriate
   // MinValue or MaxValue is used.
   virtual TypeCode GetTypeCode()
   {
      return TypeCode::Object;
   }

   virtual bool ToBoolean( IFormatProvider^ provider )
   {
      
      // ToBoolean is false if the dataset is empty.
      if ( data->Count <= 0 )
            return false;
      // For median averaging, ToBoolean is true if any 
      // non-discarded elements are nonzero.
      else
      
      // For median averaging, ToBoolean is true if any 
      // non-discarded elements are nonzero.
      if ( AverageType::Median == GetAverageInfo( provider )->TypeOfAverage )
      {
         if ( data->Count % 2 == 0 )
                  return (UnBoxDouble( data[ data->Count / 2 ] ) != 0.0 || UnBoxDouble( data[ data->Count / 2 - 1 ] ) != 0.0);
         else
                  return UnBoxDouble( data[ data->Count / 2 ] ) != 0.0;
      }
      // For arithmetic or geometric mean averaging, ToBoolean is 
      // true if any element of the dataset is nonzero.  
      else
      {
         for ( int Index = 0; Index < data->Count; Index++ )
            if ( UnBoxDouble( data[ Index ] ) != 0.0 )
                        return true;
         return false;
      }
   }

   virtual Byte ToByte( IFormatProvider^ provider )
   {
      return Convert::ToByte( CalcNLimitAverage( Byte::MinValue, Byte::MaxValue, provider ) );
   }

   virtual Char ToChar( IFormatProvider^ provider )
   {
      return Convert::ToChar( Convert::ToUInt16( CalcNLimitAverage( Char::MinValue, Char::MaxValue, provider ) ) );
   }


   // Convert to DateTime by adding the calculated average as 
   // seconds to the current date and time. A valid DateTime is 
   // always returned.
   virtual DateTime ToDateTime( IFormatProvider^ provider )
   {
      double seconds = Average( GetAverageInfo( provider )->TypeOfAverage );
      try
      {
         return DateTime::Now.AddSeconds( seconds );
      }
      catch ( ArgumentOutOfRangeException^ ) 
      {
         return seconds < 0.0 ? DateTime::MinValue : DateTime::MaxValue;
      }

   }

   virtual Decimal ToDecimal( IFormatProvider^ provider )
   {
      
      // The Double conversion rounds Decimal.MinValue and 
      // Decimal.MaxValue to invalid Decimal values, so the 
      // following limits must be used.
      return Convert::ToDecimal( CalcNLimitAverage(  -79228162514264330000000000000.0, 79228162514264330000000000000.0, provider ) );
   }

   virtual double ToDouble( IFormatProvider^ provider )
   {
      return Average( GetAverageInfo( provider )->TypeOfAverage );
   }

   virtual short ToInt16( IFormatProvider^ provider )
   {
      return Convert::ToInt16( CalcNLimitAverage( Int16::MinValue, Int16::MaxValue, provider ) );
   }

   virtual int ToInt32( IFormatProvider^ provider )
   {
      return Convert::ToInt32( CalcNLimitAverage( Int32::MinValue, Int32::MaxValue, provider ) );
   }

   virtual __int64 ToInt64( IFormatProvider^ provider )
   {
      
      // The Double conversion rounds Int64.MinValue and 
      // Int64.MaxValue to invalid Int64 values, so the following 
      // limits must be used.
      return Convert::ToInt64( CalcNLimitAverage(  -9223372036854775000, 9223372036854775000, provider ) );
   }

   virtual signed char ToSByte( IFormatProvider^ provider )
   {
      return Convert::ToSByte( CalcNLimitAverage( SByte::MinValue, SByte::MaxValue, provider ) );
   }

   virtual float ToSingle( IFormatProvider^ provider )
   {
      return Convert::ToSingle( CalcNLimitAverage( Single::MinValue, Single::MaxValue, provider ) );
   }

   virtual UInt16 ToUInt16( IFormatProvider^ provider )
   {
      return Convert::ToUInt16( CalcNLimitAverage( UInt16::MinValue, UInt16::MaxValue, provider ) );
   }

   virtual UInt32 ToUInt32( IFormatProvider^ provider )
   {
      return Convert::ToUInt32( CalcNLimitAverage( UInt32::MinValue, UInt32::MaxValue, provider ) );
   }

   virtual UInt64 ToUInt64( IFormatProvider^ provider )
   {
      
      // The Double conversion rounds UInt64.MaxValue to an invalid
      // UInt64 value, so the following limit must be used.
      return Convert::ToUInt64( CalcNLimitAverage( 0, 18446744073709550000.0, provider ) );
   }

   virtual Object^ ToType( Type^ conversionType, IFormatProvider^ provider )
   {
      return Convert::ChangeType( Average( GetAverageInfo( provider )->TypeOfAverage ), conversionType );
   }

   virtual String^ ToString( IFormatProvider^ provider )
   {
      AverageType avgType = GetAverageInfo( provider )->TypeOfAverage;
      return String::Format( "( {0}: {1:G10} )", avgType, Average( avgType ) );
   }

};


// Display a DataSet with three different format providers.
void DisplayDataSet( DataSet^ ds )
{
   IFormatProvider^ null = nullptr;
   String^ fmt = "{0,-12}{1,20}{2,20}{3,20}";
   AverageInfo^ median = gcnew AverageInfo( AverageType::Median );
   AverageInfo^ geMean = gcnew AverageInfo( AverageType::GeometricMean );
   
   // Display the dataset elements.
   if ( ds->Count > 0 )
   {
      Console::Write( "\nDataSet: [{0}", ds->Item[ 0 ] );
      for ( int iX = 1; iX < ds->Count; iX++ )
         Console::Write( ", {0}", ds->Item[ iX ] );
      Console::WriteLine( "]\n" );
   }

   Console::WriteLine( fmt, "Convert::", "Default", "Geometric Mean", "Median" );
   Console::WriteLine( fmt, "---------", "-------", "--------------", "------" );
   Console::WriteLine( fmt, "ToBoolean", Convert::ToBoolean( ds, null ), Convert::ToBoolean( ds, geMean ), Convert::ToBoolean( ds, median ) );
   Console::WriteLine( fmt, "ToByte", Convert::ToByte( ds, null ), Convert::ToByte( ds, geMean ), Convert::ToByte( ds, median ) );
   Console::WriteLine( fmt, "ToChar", Convert::ToChar( ds, null ), Convert::ToChar( ds, geMean ), Convert::ToChar( ds, median ) );
   Console::WriteLine( "{0,-12}{1,20:yyyy-MM-dd HH:mm:ss}"
   "{2,20:yyyy-MM-dd HH:mm:ss}{3,20:yyyy-MM-dd HH:mm:ss}", "ToDateTime", Convert::ToDateTime( ds, null ), Convert::ToDateTime( ds, geMean ), Convert::ToDateTime( ds, median ) );
   Console::WriteLine( fmt, "ToDecimal", Convert::ToDecimal( ds, null ), Convert::ToDecimal( ds, geMean ), Convert::ToDecimal( ds, median ) );
   Console::WriteLine( fmt, "ToDouble", Convert::ToDouble( ds, null ), Convert::ToDouble( ds, geMean ), Convert::ToDouble( ds, median ) );
   Console::WriteLine( fmt, "ToInt16", Convert::ToInt16( ds, null ), Convert::ToInt16( ds, geMean ), Convert::ToInt16( ds, median ) );
   Console::WriteLine( fmt, "ToInt32", Convert::ToInt32( ds, null ), Convert::ToInt32( ds, geMean ), Convert::ToInt32( ds, median ) );
   Console::WriteLine( fmt, "ToInt64", Convert::ToInt64( ds, null ), Convert::ToInt64( ds, geMean ), Convert::ToInt64( ds, median ) );
   Console::WriteLine( fmt, "ToSByte", Convert::ToSByte( ds, null ), Convert::ToSByte( ds, geMean ), Convert::ToSByte( ds, median ) );
   Console::WriteLine( fmt, "ToSingle", Convert::ToSingle( ds, null ), Convert::ToSingle( ds, geMean ), Convert::ToSingle( ds, median ) );
   Console::WriteLine( fmt, "ToUInt16", Convert::ToUInt16( ds, null ), Convert::ToUInt16( ds, geMean ), Convert::ToUInt16( ds, median ) );
   Console::WriteLine( fmt, "ToUInt32", Convert::ToUInt32( ds, null ), Convert::ToUInt32( ds, geMean ), Convert::ToUInt32( ds, median ) );
   Console::WriteLine( fmt, "ToUInt64", Convert::ToUInt64( ds, null ), Convert::ToUInt64( ds, geMean ), Convert::ToUInt64( ds, median ) );
}

int main()
{
   Console::WriteLine( "This example of the "
   "Convert::To<Type>( Object*, IFormatProvider* ) methods "
   "\ngenerates the following output. The example "
   "displays the values \nreturned by the methods, "
   "using several IFormatProvider objects.\n" );
   
   // To call a [ParamArray] method in C++, you cannot just
   // list the parameters, you need to build an array.
   array<Double>^dataElem = gcnew array<Double>(6);
   dataElem[ 0 ] = 10.5;
   dataElem[ 1 ] = 22.2;
   dataElem[ 2 ] = 45.9;
   dataElem[ 3 ] = 88.7;
   dataElem[ 4 ] = 156.05;
   dataElem[ 5 ] = 297.6;
   DataSet^ ds1 = gcnew DataSet( dataElem );
   DisplayDataSet( ds1 );
   dataElem = gcnew array<Double>(5);
   dataElem[ 0 ] = 359999.95;
   dataElem[ 1 ] = 425000;
   dataElem[ 2 ] = 499999.5;
   dataElem[ 3 ] = 775000;
   dataElem[ 4 ] = 1695000;
   DataSet^ ds2 = gcnew DataSet( dataElem );
   DisplayDataSet( ds2 );
}

/*
This example of the Convert::To<Type>( Object*, IFormatProvider* ) methods
generates the following output. The example displays the values
returned by the methods, using several IFormatProvider objects.

DataSet: [10.5, 22.2, 45.9, 88.7, 156.05, 297.6]

Convert::                Default      Geometric Mean              Median
---------                -------      --------------              ------
ToBoolean                   True                True                True
ToByte                       103                  59                  67
ToChar                         g                   ;                   C
ToDateTime   2003-05-13 15:30:23 2003-05-13 15:29:39 2003-05-13 15:29:47
ToDecimal       103.491666666667    59.4332135445164                67.3
ToDouble        103.491666666667    59.4332135445164                67.3
ToInt16                      103                  59                  67
ToInt32                      103                  59                  67
ToInt64                      103                  59                  67
ToSByte                      103                  59                  67
ToSingle                103.4917            59.43321                67.3
ToUInt16                     103                  59                  67
ToUInt32                     103                  59                  67
ToUInt64                     103                  59                  67

DataSet: [359999.95, 425000, 499999.5, 775000, 1695000]

Convert::                Default      Geometric Mean              Median
---------                -------      --------------              ------
ToBoolean                   True                True                True
ToByte                       255                 255                 255
ToChar                         ?                   ?                   ?
ToDateTime   2003-05-22 08:05:19 2003-05-20 22:54:57 2003-05-19 10:21:59
ToDecimal              750999.89    631577.237188435            499999.5
ToDouble               750999.89    631577.237188435            499999.5
ToInt16                    32767               32767               32767
ToInt32                   751000              631577              500000
ToInt64                   751000              631577              500000
ToSByte                      127                 127                 127
ToSingle                750999.9            631577.3            499999.5
ToUInt16                   65535               65535               65535
ToUInt32                  751000              631577              500000
ToUInt64                  751000              631577              500000
*/

using System;
using System.Collections;

// Define the types of averaging available in the class
// implementing IConvertible.
public enum AverageType : short
{
    None = 0,
    GeometricMean = 1,
    ArithmeticMean = 2,
    Median = 3
};

// Pass an instance of this class to methods that require an
// IFormatProvider. The class instance determines the type of
// average to calculate.
public class AverageInfo : IFormatProvider
{
    protected AverageType AvgType;

    // Specify the type of averaging in the constructor.
    public AverageInfo( AverageType avgType )
    {
        this.AvgType = avgType;
    }

    // This method returns a reference to the containing object
    // if an object of AverageInfo type is requested.
    public object GetFormat( Type argType )
    {
        if ( argType == typeof( AverageInfo ) )
            return this;
        else
            return null;
    }

    // Use this property to set or get the type of averaging.
    public AverageType TypeOfAverage
    {
        get { return this.AvgType; }
        set { this.AvgType = value; }
    }
}

// This class encapsulates an array of double values and implements
// the IConvertible interface. Most of the IConvertible methods
// return an average of the array elements in one of three types:
// arithmetic mean, geometric mean, or median.
public class DataSet : IConvertible
{
    protected ArrayList     data;
    protected AverageInfo   defaultProvider;

    // Construct the object and add an initial list of values.
    // Create a default format provider.
    public DataSet( params double[ ] values )
    {
        data = new ArrayList( values );
        defaultProvider =
            new AverageInfo( AverageType.ArithmeticMean );
    }

    // Add additional values with this method.
    public int Add( double value )
    {
        data.Add( value );
        return data.Count;
    }

    // Get, set, and add values with this indexer property.
    public double this[ int index ]
    {
        get
        {
            if( index >= 0 && index < data.Count )
                return (double)data[ index ];
            else
                throw new InvalidOperationException(
                    "[DataSet.get] Index out of range." );
        }
        set
        {
            if( index >= 0 && index < data.Count )
                data[ index ] = value;

            else if( index == data.Count )
                data.Add( value );
            else
                throw new InvalidOperationException(
                    "[DataSet.set] Index out of range." );
        }
    }

    // This property returns the number of elements in the object.
    public int Count
    {
        get { return data.Count; }
    }

    // This method calculates the average of the object's elements.
    protected double Average( AverageType avgType )
    {
        double  SumProd;

        if( data.Count == 0 )
            return 0.0;

        switch( avgType )
        {
            case AverageType.GeometricMean:

                SumProd = 1.0;
                for( int Index = 0; Index < data.Count; Index++ )
                    SumProd *= (double)data[ Index ];

                // This calculation will not fail with negative
                // elements.
                return Math.Sign( SumProd ) * Math.Pow(
                    Math.Abs( SumProd ), 1.0 / data.Count );

            case AverageType.ArithmeticMean:

                SumProd = 0.0;
                for( int Index = 0; Index < data.Count; Index++ )
                    SumProd += (double)data[ Index ];

                return SumProd / data.Count;

            case AverageType.Median:

                if( data.Count % 2 == 0 )
                    return ( (double)data[ data.Count / 2 ] +
                        (double)data[ data.Count / 2 - 1 ] ) / 2.0;
                else
                    return (double)data[ data.Count / 2 ];

            default:
                return 0.0;
        }
    }

    // Get the AverageInfo object from the caller's format provider,
    // or use the local default.
    protected AverageInfo GetAverageInfo( IFormatProvider provider )
    {
        AverageInfo avgInfo = null;

        if( provider != null )
            avgInfo = (AverageInfo)provider.GetFormat(
                typeof( AverageInfo ) );

        if ( avgInfo == null )
            return defaultProvider;
        else
            return avgInfo;
    }

    // Calculate the average and limit the range.
    protected double CalcNLimitAverage( double min, double max,
        IFormatProvider provider )
    {
        // Get the format provider and calculate the average.
        AverageInfo avgInfo = GetAverageInfo( provider );
        double avg = Average( avgInfo.TypeOfAverage );

        // Limit the range, based on the minimum and maximum values
        // for the type.
        return avg > max ? max : avg < min ? min : avg;
    }

    // The following elements are required by IConvertible.

    // None of these conversion functions throw exceptions. When
    // the data is out of range for the type, the appropriate
    // MinValue or MaxValue is used.
    public TypeCode GetTypeCode( )
    {
        return TypeCode.Object;
    }

    public bool ToBoolean( IFormatProvider provider )
    {
        // ToBoolean is false if the dataset is empty.
        if( data.Count <= 0 )
        {
            return false;
        }

        // For median averaging, ToBoolean is true if any
        // non-discarded elements are nonzero.
        else if( AverageType.Median ==
            GetAverageInfo( provider ).TypeOfAverage )
        {
            if (data.Count % 2 == 0 )
                return ( (double)data[ data.Count / 2 ] != 0.0 ||
                    (double)data[ data.Count / 2 - 1 ] != 0.0 );
            else
                return (double)data[ data.Count / 2 ] != 0.0;
        }

        // For arithmetic or geometric mean averaging, ToBoolean is
        // true if any element of the dataset is nonzero.
        else
        {
            for( int Index = 0; Index < data.Count; Index++ )
                if( (double)data[ Index ] != 0.0 )
                    return true;
            return false;
        }
    }

    public byte ToByte( IFormatProvider provider )
    {
        return Convert.ToByte( CalcNLimitAverage(
            Byte.MinValue, Byte.MaxValue, provider ) );
    }

    public char ToChar( IFormatProvider provider )
    {
        return Convert.ToChar( Convert.ToUInt16( CalcNLimitAverage(
            Char.MinValue, Char.MaxValue, provider ) ) );
    }

    // Convert to DateTime by adding the calculated average as
    // seconds to the current date and time. A valid DateTime is
    // always returned.
    public DateTime ToDateTime( IFormatProvider provider )
    {
        double seconds =
            Average( GetAverageInfo( provider ).TypeOfAverage );
        try
        {
            return DateTime.Now.AddSeconds( seconds );
        }
        catch( ArgumentOutOfRangeException )
        {
            return seconds < 0.0 ? DateTime.MinValue : DateTime.MaxValue;
        }
    }

    public decimal ToDecimal( IFormatProvider provider )
    {
        // The Double conversion rounds Decimal.MinValue and
        // Decimal.MaxValue to invalid Decimal values, so the
        // following limits must be used.
        return Convert.ToDecimal( CalcNLimitAverage(
            -79228162514264330000000000000.0,
            79228162514264330000000000000.0, provider ) );
    }

    public double ToDouble( IFormatProvider provider )
    {
        return Average( GetAverageInfo(provider).TypeOfAverage );
    }

    public short ToInt16( IFormatProvider provider )
    {
        return Convert.ToInt16( CalcNLimitAverage(
            Int16.MinValue, Int16.MaxValue, provider ) );
    }

    public int ToInt32( IFormatProvider provider )
    {
        return Convert.ToInt32( CalcNLimitAverage(
            Int32.MinValue, Int32.MaxValue, provider ) );
    }

    public long ToInt64( IFormatProvider provider )
    {
        // The Double conversion rounds Int64.MinValue and
        // Int64.MaxValue to invalid Int64 values, so the following
        // limits must be used.
        return Convert.ToInt64( CalcNLimitAverage(
            -9223372036854775000, 9223372036854775000, provider ) );
    }

    public SByte ToSByte( IFormatProvider provider )
    {
        return Convert.ToSByte( CalcNLimitAverage(
            SByte.MinValue, SByte.MaxValue, provider ) );
    }

    public float ToSingle( IFormatProvider provider )
    {
        return Convert.ToSingle( CalcNLimitAverage(
            Single.MinValue, Single.MaxValue, provider ) );
    }

    public UInt16 ToUInt16( IFormatProvider provider )
    {
        return Convert.ToUInt16( CalcNLimitAverage(
            UInt16.MinValue, UInt16.MaxValue, provider ) );
    }

    public UInt32 ToUInt32( IFormatProvider provider )
    {
        return Convert.ToUInt32( CalcNLimitAverage(
            UInt32.MinValue, UInt32.MaxValue, provider ) );
    }

    public UInt64 ToUInt64( IFormatProvider provider )
    {
        // The Double conversion rounds UInt64.MaxValue to an invalid
        // UInt64 value, so the following limit must be used.
        return Convert.ToUInt64( CalcNLimitAverage(
            0, 18446744073709550000.0, provider ) );
    }

    public object ToType( Type conversionType,
        IFormatProvider provider )
    {
        return Convert.ChangeType( Average(
            GetAverageInfo( provider ).TypeOfAverage ),
            conversionType );
    }

    public string ToString( IFormatProvider provider )
    {
        AverageType avgType = GetAverageInfo( provider ).TypeOfAverage;
        return String.Format( "( {0}: {1:G10} )", avgType,
            Average( avgType ) );
    }
}

class IConvertibleProviderDemo
{
    // Display a DataSet with three different format providers.
    public static void DisplayDataSet( DataSet ds )
    {
        string      fmt    = "{0,-12}{1,20}{2,20}{3,20}";
        AverageInfo median = new AverageInfo( AverageType.Median );
        AverageInfo geMean =
            new AverageInfo( AverageType.GeometricMean );

         // Display the dataset elements.
        if( ds.Count > 0 )
        {
            Console.Write( "\nDataSet: [{0}", ds[ 0 ] );
            for( int iX = 1; iX < ds.Count; iX++ )
                Console.Write( ", {0}", ds[ iX ] );
            Console.WriteLine( "]\n" );
        }

        Console.WriteLine( fmt, "Convert.", "Default",
            "Geometric Mean", "Median");
        Console.WriteLine( fmt, "--------", "-------",
            "--------------", "------");
        Console.WriteLine( fmt, "ToBoolean",
            Convert.ToBoolean( ds, null ),
            Convert.ToBoolean( ds, geMean ),
            Convert.ToBoolean( ds, median ) );
        Console.WriteLine( fmt, "ToByte",
            Convert.ToByte( ds, null ),
            Convert.ToByte( ds, geMean ),
            Convert.ToByte( ds, median ) );
        Console.WriteLine( fmt, "ToChar",
            Convert.ToChar( ds, null ),
            Convert.ToChar( ds, geMean ),
            Convert.ToChar( ds, median ) );
        Console.WriteLine( "{0,-12}{1,20:yyyy-MM-dd HH:mm:ss}" +
            "{2,20:yyyy-MM-dd HH:mm:ss}{3,20:yyyy-MM-dd HH:mm:ss}",
            "ToDateTime", Convert.ToDateTime( ds, null ),
            Convert.ToDateTime( ds, geMean ),
            Convert.ToDateTime( ds, median ) );
        Console.WriteLine( fmt, "ToDecimal",
            Convert.ToDecimal( ds, null ),
            Convert.ToDecimal( ds, geMean ),
            Convert.ToDecimal( ds, median ) );
        Console.WriteLine( fmt, "ToDouble",
            Convert.ToDouble( ds, null ),
            Convert.ToDouble( ds, geMean ),
            Convert.ToDouble( ds, median ) );
        Console.WriteLine( fmt, "ToInt16",
            Convert.ToInt16( ds, null ),
            Convert.ToInt16( ds, geMean ),
            Convert.ToInt16( ds, median ) );
        Console.WriteLine( fmt, "ToInt32",
            Convert.ToInt32( ds, null ),
            Convert.ToInt32( ds, geMean ),
            Convert.ToInt32( ds, median ) );
        Console.WriteLine( fmt, "ToInt64",
            Convert.ToInt64( ds, null ),
            Convert.ToInt64( ds, geMean ),
            Convert.ToInt64( ds, median ) );
        Console.WriteLine( fmt, "ToSByte",
            Convert.ToSByte( ds, null ),
            Convert.ToSByte( ds, geMean ),
            Convert.ToSByte( ds, median ) );
        Console.WriteLine( fmt, "ToSingle",
            Convert.ToSingle( ds, null ),
            Convert.ToSingle( ds, geMean ),
            Convert.ToSingle( ds, median ) );
        Console.WriteLine( fmt, "ToUInt16",
            Convert.ToUInt16( ds, null ),
            Convert.ToUInt16( ds, geMean ),
            Convert.ToUInt16( ds, median ) );
        Console.WriteLine( fmt, "ToUInt32",
            Convert.ToUInt32( ds, null ),
            Convert.ToUInt32( ds, geMean ),
            Convert.ToUInt32( ds, median ) );
        Console.WriteLine( fmt, "ToUInt64",
            Convert.ToUInt64( ds, null ),
            Convert.ToUInt64( ds, geMean ),
            Convert.ToUInt64( ds, median ) );
    }

    public static void Main( )
    {
        Console.WriteLine( "This example of " +
            "the Convert.To<Type>( object, IFormatProvider ) methods " +
            "\ngenerates the following output. The example " +
            "displays the values \nreturned by the methods, " +
            "using several IFormatProvider objects.\n" );

        DataSet ds1 = new DataSet(
            10.5, 22.2, 45.9, 88.7, 156.05, 297.6 );
        DisplayDataSet( ds1 );

        DataSet ds2 = new DataSet(
            359999.95, 425000, 499999.5, 775000, 1695000 );
        DisplayDataSet( ds2 );
    }
}

/*
This example of the Convert.To<Type>( object, IFormatProvider ) methods
generates the following output. The example displays the values
returned by the methods, using several IFormatProvider objects.

DataSet: [10.5, 22.2, 45.9, 88.7, 156.05, 297.6]

Convert.                 Default      Geometric Mean              Median
--------                 -------      --------------              ------
ToBoolean                   True                True                True
ToByte                       103                  59                  67
ToChar                         g                   ;                   C
ToDateTime   2003-05-13 15:04:12 2003-05-13 15:03:28 2003-05-13 15:03:35
ToDecimal       103.491666666667    59.4332135445164                67.3
ToDouble        103.491666666667    59.4332135445164                67.3
ToInt16                      103                  59                  67
ToInt32                      103                  59                  67
ToInt64                      103                  59                  67
ToSByte                      103                  59                  67
ToSingle                103.4917            59.43321                67.3
ToUInt16                     103                  59                  67
ToUInt32                     103                  59                  67
ToUInt64                     103                  59                  67

DataSet: [359999.95, 425000, 499999.5, 775000, 1695000]

Convert.                 Default      Geometric Mean              Median
--------                 -------      --------------              ------
ToBoolean                   True                True                True
ToByte                       255                 255                 255
ToChar                         ?                   ?                   ?
ToDateTime   2003-05-22 07:39:08 2003-05-20 22:28:45 2003-05-19 09:55:48
ToDecimal              750999.89    631577.237188435            499999.5
ToDouble               750999.89    631577.237188435            499999.5
ToInt16                    32767               32767               32767
ToInt32                   751000              631577              500000
ToInt64                   751000              631577              500000
ToSByte                      127                 127                 127
ToSingle                750999.9            631577.3            499999.5
ToUInt16                   65535               65535               65535
ToUInt32                  751000              631577              500000
ToUInt64                  751000              631577              500000
*/

Imports System.Collections

Module IConvertibleProviderDemo

    ' Define the types of averaging available in the class 
    ' implementing IConvertible.
    Enum AverageType as Short
        None = 0
        GeometricMean = 1
        ArithmeticMean = 2
        Median = 3
    End Enum

    ' Pass an instance of this class to methods that require an 
    ' IFormatProvider. The class instance determines the type of 
    ' average to calculate.
    Public Class AverageInfo
        Implements IFormatProvider

        Protected  AvgType      As AverageType

        ' Specify the type of averaging in the constructor.
        Public Sub New( avgType As AverageType )
            Me.AvgType = avgType
        End Sub

        ' This method returns a reference to the containing object 
        ' if an object of AverageInfo type is requested. 
        Public Function GetFormat( argType As Type ) As Object _
            Implements IFormatProvider.GetFormat

            If argType Is GetType( AverageInfo ) Then
                Return Me
            Else
                Return Nothing
            End If
        End Function 

        ' Use this property to set or get the type of averaging.
        Public Property TypeOfAverage( ) As AverageType
            Get
                Return Me.AvgType
            End Get
            Set( ByVal value as AverageType )
                Me.AvgType = value
            End Set
        End Property
    End Class 

    ' This class encapsulates an array of Double values and implements 
    ' the IConvertible interface. Most of the IConvertible methods 
    ' return an average of the array elements in one of three types: 
    ' arithmetic mean, geometric mean, or median. 
    Public Class DataSet
        Implements IConvertible

        Protected data              As ArrayList
        Protected defaultProvider   As AverageInfo
           
        ' Construct the object and add an initial list of values.
        ' Create a default format provider.
        Public Sub New( ParamArray values( ) As Double )
            data = New ArrayList( values )
            defaultProvider = New AverageInfo( _
                AverageType.ArithmeticMean )  
        End Sub
           
        ' Add additional values with this method.
        Public Function Add( value As Double ) As Integer
            data.Add( value )
            Return data.Count
        End Function
           
        ' Get, set, and add values with this indexer property.
        Default Public Property Item(index As Integer) As Double
            Get
                If index >= 0 AndAlso index < data.Count Then
                    Return System.Convert.ToDouble( data( index ) )
                Else
                    Throw New InvalidOperationException( _
                        "[DataSet.get] Index out of range." )
                End If
            End Get
            Set
                If index >= 0 AndAlso index < data.Count Then
                    data( index ) = value
                 
                ElseIf index = data.Count Then
                    data.Add( value )
                Else
                    Throw New InvalidOperationException( _
                        "[DataSet.set] Index out of range." )
                End If
            End Set
        End Property
          
        ' This property returns the number of elements in the object.
        Public ReadOnly Property Count( ) As Integer
            Get
                Return data.Count
            End Get
        End Property

        ' This method calculates the average of the object's elements.
        Protected Function Average( ByVal avgType As AverageType ) As Double

            Dim SumProd As Double 
            Dim Index   As Integer

            If data.Count = 0 Then Return 0.0

            Select Case avgType
                
                Case AverageType.GeometricMean

                    SumProd = 1.0
                    For Index = 0 To data.Count - 1
                        SumProd *= data( Index )
                    Next Index
                    
                    ' This calculation will not fail with negative 
                    ' elements.
                    Return Math.Sign( SumProd ) * Math.Pow( _
                        Math.Abs( SumProd ), 1.0 / data.Count )

                Case AverageType.ArithmeticMean

                    SumProd = 0.0
                    For Index = 0 To data.Count - 1
                        SumProd += data( Index )
                    Next Index

                    Return SumProd / data.Count 

                Case AverageType.Median

                    If data.Count Mod 2 = 0 Then
                        Return ( data( data.Count \ 2 ) + _
                            data( data.Count \ 2 - 1 ) ) / 2.0
                    Else
                        Return data( data.Count \ 2 ) 
                    End If
            End Select
        End Function

        ' Get the AverageInfo object from the caller's format 
        ' provider, or use the local default.
        Protected Function GetAverageInfo( _
            provider As IFormatProvider ) As AverageInfo

            Dim avgInfo As AverageInfo = Nothing

            If Not provider Is Nothing Then
                avgInfo = provider.GetFormat( GetType( AverageInfo ) )
            End If

            Return IIf( avgInfo Is Nothing, defaultProvider, avgInfo )
            
        End Function           

        ' Calculate the average and limit the range.
        Protected Function CalcNLimitAverage( min As Double, _
            max As Double, provider as IFormatProvider ) As Double

            ' Get the format provider and calculate the average.
            Dim avgInfo As AverageInfo = GetAverageInfo( provider )
            Dim avg As Double = Average( avgInfo.TypeOfAverage )

            ' Limit the range, based on the minimum and maximum values 
            ' for the type.
            Return IIf( avg > max, max, IIf( avg < min, min, avg ) )

        End Function

        ' The following elements are required by IConvertible.

        ' None of these conversion functions throw exceptions. When
        ' the data is out of range for the type, the appropriate
        ' MinValue or MaxValue is used.
        Public Function GetTypeCode( ) As TypeCode _
            Implements IConvertible.GetTypeCode
            Return TypeCode.Object
        End Function

        Function ToBoolean( ByVal provider As IFormatProvider ) As _
            Boolean Implements IConvertible.ToBoolean

            ' ToBoolean is false if the dataset is empty.
            If data.Count <= 0 Then
                Return False

            ' For median averaging, ToBoolean is true if any 
            ' non-discarded elements are nonzero.
            ElseIf AverageType.Median = _
                GetAverageInfo( provider ).TypeOfAverage Then

                If data.Count Mod 2 = 0 Then
                    Return ( data( data.Count \ 2 ) <> 0.0 Or _
                        data( data.Count \ 2 - 1 ) <> 0.0 )
                Else
                    Return data( data.Count \ 2 ) <> 0.0
                End If

            ' For arithmetic or geometric mean averaging, ToBoolean is 
            ' true if any element of the dataset is nonzero.  
            Else
                Dim Index As Integer
                For Index = 0 To data.Count - 1
                    If data( Index ) <> 0.0 Then Return True
                Next Index
                Return False
            End If
        End Function

        Function ToByte( ByVal provider As IFormatProvider ) As Byte _
            Implements IConvertible.ToByte
            Return Convert.ToByte( CalcNLimitAverage( _
                Byte.MinValue, Byte.MaxValue, provider ) )
        End Function

        Function ToChar( ByVal provider As IFormatProvider ) As Char _
            Implements IConvertible.ToChar
            Return Convert.ToChar( Convert.ToUInt16( _
                CalcNLimitAverage( 0.0, &HFFFF, provider ) ) )
        End Function

        ' Convert to DateTime by adding the calculated average as 
        ' seconds to the current date and time. A valid DateTime is 
        ' always returned.
        Function ToDateTime( ByVal provider As IFormatProvider ) As _
            DateTime Implements IConvertible.ToDateTime
            Dim seconds As Double = Average( _
                GetAverageInfo( provider ).TypeOfAverage )
            Try
                Return DateTime.Now.AddSeconds( seconds )
            Catch ex As ArgumentOutOfRangeException 
                Return IIf( seconds < 0.0, DateTime.MinValue, _
                    DateTime.MaxValue )
            End Try
        End Function

        Function ToDecimal( ByVal provider As IFormatProvider ) As _
            Decimal Implements IConvertible.ToDecimal

            ' The Double conversion rounds Decimal.MinValue and
            ' Decimal.MaxValue to invalid Decimal values, so the 
            ' following limits must be used.
            Return Convert.ToDecimal( CalcNLimitAverage( _
                -79228162514264330000000000000.0, _
                79228162514264330000000000000.0, provider ) )
        End Function

        Function ToDouble( ByVal provider As IFormatProvider) As _
            Double Implements IConvertible.ToDouble
            Return Average( GetAverageInfo( provider ).TypeOfAverage )
        End Function

        Function ToInt16( ByVal provider As IFormatProvider ) As _
            Short Implements IConvertible.ToInt16
            Return Convert.ToInt16( CalcNLimitAverage( _
                Int16.MinValue, Int16.MaxValue, provider ) )
        End Function

        Function ToInt32( ByVal provider As IFormatProvider ) As _
            Integer Implements IConvertible.ToInt32
            Return Convert.ToInt32( CalcNLimitAverage( _
                Int32.MinValue, Int32.MaxValue, provider ) )
        End Function

        Function ToInt64( ByVal provider As IFormatProvider ) As Long _
            Implements IConvertible.ToInt64

            ' The Double conversion rounds Int64.MinValue and 
            ' Int64.MaxValue to invalid Long values, so the following 
            ' limits must be used.
            Return Convert.ToInt64( CalcNLimitAverage( _
                -9223372036854775000, 9223372036854775000, provider ) )
        End Function

        Function ToSByte( ByVal provider As IFormatProvider ) As _
            SByte Implements IConvertible.ToSByte

            ' SByte.MinValue and SByte.MaxValue are not defined in
            ' Visual Basic.
            Return Convert.ToSByte( CalcNLimitAverage( _
                -128, 127, provider ) )
        End Function

        Function ToSingle( ByVal provider As IFormatProvider ) As _
            Single Implements IConvertible.ToSingle
            Return Convert.ToSingle( CalcNLimitAverage( _
                Single.MinValue, Single.MaxValue, provider ) )
        End Function

        Function ToUInt16( ByVal provider As IFormatProvider ) As _
            UInt16 Implements IConvertible.ToUInt16

            ' UInt16.MinValue and UInt16.MaxValue are not defined in 
            ' Visual Basic.
            Return Convert.ToUInt16( CalcNLimitAverage( _
                0, &HFFFF, provider ) )
        End Function

        Function ToUInt32( ByVal provider As IFormatProvider ) As _
            UInt32 Implements IConvertible.ToUInt32

            ' UInt32.MinValue and UInt32.MaxValue are not defined in 
            ' Visual Basic.
            Return Convert.ToUInt32( CalcNLimitAverage( _
                0, 4294967295, provider ) )
        End Function

        Function ToUInt64( ByVal provider As IFormatProvider ) As _
            UInt64 Implements IConvertible.ToUInt64

            ' UInt64.MinValue and UInt64.MaxValue are not defined in 
            ' Visual Basic. The Double conversion would have rounded 
            ' UInt64.MaxValue, so the following limit must be used.
            Return Convert.ToUInt64( CalcNLimitAverage( _
                0, 18446744073709550000.0, provider ) )
        End Function

        Function ToType( ByVal conversionType As Type, _
            ByVal provider As IFormatProvider) As Object _
            Implements IConvertible.ToType
            Return Convert.ChangeType( Average( GetAverageInfo( _
                provider ).TypeOfAverage ), conversionType )
        End Function

        Overloads Function ToString( ByVal provider As IFormatProvider _
            ) As String Implements IConvertible.ToString
            Dim avgType as AverageType = _
                GetAverageInfo( provider ).TypeOfAverage
            Return String.Format( "( {0}: {1:G10} )", avgType, _
                Average( avgType ) )
        End Function
    End Class
   
    ' Display a DataSet with three different format providers.
    Sub DisplayDataSet( ds As DataSet )

        Dim fmt    As String      = "{0,-12}{1,20}{2,20}{3,20}"
        Dim median As AverageInfo = New AverageInfo( AverageType.Median )
        Dim geMean As AverageInfo = _
            New AverageInfo( AverageType.GeometricMean )
        Dim iX     As Integer

        ' Display the dataset elements.
        If ds.Count > 0 Then
            Console.Write( vbCrLf & "DataSet: [{0}", ds( 0 ) )
            For iX = 1 To ds.Count - 1
                Console.Write( ", {0}", ds( iX ) )
            Next iX
            Console.WriteLine( "]" & vbCrLf )
        End If

        Console.WriteLine( fmt, "Convert.", "Default", _
            "Geometric Mean", "Median" )
        Console.WriteLine( fmt, "--------", "-------", _
            "--------------", "------" )
        Console.WriteLine( fmt, "ToBoolean", _
            Convert.ToBoolean( ds, Nothing ), _
            Convert.ToBoolean( ds, geMean ), _
            Convert.ToBoolean( ds, median ) )
        Console.WriteLine( fmt, "ToByte", _
            Convert.ToByte( ds, Nothing ), _
            Convert.ToByte( ds, geMean ), _
            Convert.ToByte( ds, median ) )
        Console.WriteLine( fmt, "ToChar", _
            Convert.ToChar( ds, Nothing ), _
            Convert.ToChar( ds, geMean ), _
            Convert.ToChar( ds, median ) )
        Console.WriteLine( "{0,-12}{1,20:yyyy-MM-dd HH:mm:ss}" & _
            "{2,20:yyyy-MM-dd HH:mm:ss}{3,20:yyyy-MM-dd HH:mm:ss}", _
            "ToDateTime", Convert.ToDateTime( ds, Nothing ), _
            Convert.ToDateTime( ds, geMean ), _
            Convert.ToDateTime( ds, median ) )
        Console.WriteLine( fmt, "ToDecimal", _
            Convert.ToDecimal( ds, Nothing ), _
            Convert.ToDecimal( ds, geMean ), _
            Convert.ToDecimal( ds, median ) )
        Console.WriteLine( fmt, "ToDouble", _
            Convert.ToDouble( ds, Nothing ), _
            Convert.ToDouble( ds, geMean ), _
            Convert.ToDouble( ds, median ) )
        Console.WriteLine( fmt, "ToInt16", _
            Convert.ToInt16( ds, Nothing ), _
            Convert.ToInt16( ds, geMean ), _
            Convert.ToInt16( ds, median ) )
        Console.WriteLine( fmt, "ToInt32", _
            Convert.ToInt32( ds, Nothing ), _
            Convert.ToInt32( ds, geMean ), _
            Convert.ToInt32( ds, median ) )
        Console.WriteLine( fmt, "ToInt64", _
            Convert.ToInt64( ds, Nothing ), _
            Convert.ToInt64( ds, geMean ), _
            Convert.ToInt64( ds, median ) )
        Console.WriteLine( fmt, "ToSByte", _
            Convert.ToSByte( ds, Nothing ), _
            Convert.ToSByte( ds, geMean ), _
            Convert.ToSByte( ds, median ) )
        Console.WriteLine( fmt, "ToSingle", _
            Convert.ToSingle( ds, Nothing ), _
            Convert.ToSingle( ds, geMean ), _
            Convert.ToSingle( ds, median ) )
        Console.WriteLine( fmt, "ToUInt16", _
            Convert.ToUInt16( ds, Nothing ), _
            Convert.ToUInt16( ds, geMean ), _
            Convert.ToUInt16( ds, median ) )
        Console.WriteLine( fmt, "ToUInt32", _
            Convert.ToUInt32( ds, Nothing ), _
            Convert.ToUInt32( ds, geMean ), _
            Convert.ToUInt32( ds, median ) )
        Console.WriteLine( fmt, "ToUInt64", _
            Convert.ToUInt64( ds, Nothing ), _
            Convert.ToUInt64( ds, geMean ), _
            Convert.ToUInt64( ds, median ) )
    End Sub
   
    Sub Main( )
        Console.WriteLine( _
            "This example of the Convert.To<Type>( Object, " & _
            "IFormatProvider ) methods " & vbCrLf & "generates " & _
            "the following output. The example displays the " & _
            "values " & vbCrLf & "returned by the methods, " & _
            "using several IFormatProvider objects." & vbCrLf )
          
        Dim ds1 As New DataSet( 10.5, 22.2, 45.9, 88.7, 156.05, 297.6 )
        DisplayDataSet( ds1 )
          
        Dim ds2 As New DataSet( _
            359999.95, 425000, 499999.5, 775000, 1695000 )
        DisplayDataSet( ds2 )
    End Sub 
End Module 

' This example of the Convert.To<Type>( Object, IFormatProvider ) methods
' generates the following output. The example displays the values
' returned by the methods, using several IFormatProvider objects.
' 
' DataSet: [10.5, 22.2, 45.9, 88.7, 156.05, 297.6]
' 
' Convert.                 Default      Geometric Mean              Median
' --------                 -------      --------------              ------
' ToBoolean                   True                True                True
' ToByte                       103                  59                  67
' ToChar                         g                   ;                   C
' ToDateTime   2003-05-13 14:52:53 2003-05-13 14:52:09 2003-05-13 14:52:17
' ToDecimal       103.491666666667    59.4332135445164                67.3
' ToDouble        103.491666666667    59.4332135445164                67.3
' ToInt16                      103                  59                  67
' ToInt32                      103                  59                  67
' ToInt64                      103                  59                  67
' ToSByte                      103                  59                  67
' ToSingle                103.4917            59.43321                67.3
' ToUInt16                     103                  59                  67
' ToUInt32                     103                  59                  67
' ToUInt64                     103                  59                  67
' 
' DataSet: [359999.95, 425000, 499999.5, 775000, 1695000]
' 
' Convert.                 Default      Geometric Mean              Median
' --------                 -------      --------------              ------
' ToBoolean                   True                True                True
' ToByte                       255                 255                 255
' ToChar                         ?                   ?                   ?
' ToDateTime   2003-05-22 07:27:49 2003-05-20 22:17:27 2003-05-19 09:44:29
' ToDecimal              750999.89    631577.237188435            499999.5
' ToDouble               750999.89    631577.237188435            499999.5
' ToInt16                    32767               32767               32767
' ToInt32                   751000              631577              500000
' ToInt64                   751000              631577              500000
' ToSByte                      127                 127                 127
' ToSingle                750999.9            631577.3            499999.5
' ToUInt16                   65535               65535               65535
' ToUInt32                  751000              631577              500000
' ToUInt64                  751000              631577              500000

注解

provider 使用户能够指定有关的内容的特定于区域性的转换信息 value 。provider enables the user to specify culture-specific conversion information about the contents of value. 例如，如果 value 是表示数字的，则 String provider 可能提供有关用于表示该数字的表示法的区域性特定信息。For example, if value is a String that represents a number, provider could supply culture-specific information about the notation used to represent that number.

基类型将忽略 provider ; 但是，如果 value 是实现接口的用户定义类型，则可以使用参数 IConvertible 。The base types ignore provider; however, the parameter may be used if value is a user-defined type that implements the IConvertible interface.

public:
 static short ToInt16(System::UInt64 value);

public static short ToInt16 (ulong value);

[System.CLSCompliant(false)]
public static short ToInt16 (ulong value);

static member ToInt16 : uint64 -> int16

[<System.CLSCompliant(false)>]
static member ToInt16 : uint64 -> int16

Public Shared Function ToInt16 (value As ULong) As Short

参数

返回

Int16

一个与 value 等效的 16 位带符号整数。A 16-bit signed integer that is equivalent to value.

属性

CLSCompliantAttribute

例外

示例

下面的示例尝试将无符号长整数数组中的每个元素转换为16位带符号整数。The following example attempts to convert each element in an array of unsigned long integers to a 16-bit signed integer.

ulong[] numbers = { UInt64.MinValue, 121, 340, UInt64.MaxValue };
short result;

foreach (ulong number in numbers)
{
   try {
      result = Convert.ToInt16(number);
      Console.WriteLine("Converted the {0} value {1} to a {2} value {3}.",
                        number.GetType().Name, number,
                        result.GetType().Name, result);
   }
   catch (OverflowException) {
      Console.WriteLine("The {0} value {1} is outside the range of the Int16 type.",
                        number.GetType().Name, number);
   }
}
// The example displays the following output:
//    Converted the UInt64 value 0 to a Int16 value 0.
//    Converted the UInt64 value 121 to a Int16 value 121.
//    Converted the UInt64 value 340 to a Int16 value 340.
//    The UInt64 value 18446744073709551615 is outside the range of the Int16 type.

Dim numbers() As ULong = { UInt64.MinValue, 121, 340, UInt64.MaxValue }
Dim result As Short
For Each number As ULong In numbers
   Try
      result = Convert.ToInt16(number)
      Console.WriteLine("Converted the {0} value {1} to a {2} value {3}.", _
                        number.GetType().Name, number, _
                        result.GetType().Name, result)
   Catch e As OverflowException
      Console.WriteLine("The {0} value {1} is outside the range of the Int16 type.", _
                        number.GetType().Name, number)
   End Try
Next
' The example displays the following output:
'    Converted the UInt64 value 0 to a Int16 value 0.
'    Converted the UInt64 value 121 to a Int16 value 121.
'    Converted the UInt64 value 340 to a Int16 value 340.
'    The UInt64 value 18446744073709551615 is outside the range of the Int16 type.

public:
 static short ToInt16(System::UInt32 value);

public static short ToInt16 (uint value);

[System.CLSCompliant(false)]
public static short ToInt16 (uint value);

static member ToInt16 : uint32 -> int16

[<System.CLSCompliant(false)>]
static member ToInt16 : uint32 -> int16

Public Shared Function ToInt16 (value As UInteger) As Short

参数

返回

Int16

一个与 value 等效的 16 位带符号整数。A 16-bit signed integer that is equivalent to value.

属性

CLSCompliantAttribute

例外

示例

下面的示例尝试将无符号整数数组中的每个元素转换为16位带符号整数。The following example attempts to convert each element in an array of unsigned integers to a 16-bit signed integer.

uint[] numbers = { UInt32.MinValue, 121, 340, UInt32.MaxValue };
short result;

foreach (uint number in numbers)
{
   try {
      result = Convert.ToInt16(number);
      Console.WriteLine("Converted the {0} value {1} to a {2} value {3}.",
                        number.GetType().Name, number,
                        result.GetType().Name, result);
   }
   catch (OverflowException) {
      Console.WriteLine("The {0} value {1} is outside the range of the Int16 type.",
                        number.GetType().Name, number);
   }
}
// The example displays the following output:
//    Converted the UInt32 value 0 to a Int16 value 0.
//    Converted the UInt32 value 121 to a Int16 value 121.
//    Converted the UInt32 value 340 to a Int16 value 340.
//    The UInt32 value 4294967295 is outside the range of the Int16 type.

Dim numbers() As UInteger = { UInt32.MinValue, 121, 340, UInt32.MaxValue }
Dim result As Short
For Each number As UInteger In numbers
   Try
      result = Convert.ToInt16(number)
      Console.WriteLine("Converted the {0} value {1} to a {2} value {3}.", _
                        number.GetType().Name, number, _
                        result.GetType().Name, result)
   Catch e As OverflowException
      Console.WriteLine("The {0} value {1} is outside the range of the Int16 type.", _
                        number.GetType().Name, number)
   End Try
Next
' The example displays the following output:
'    Converted the UInt32 value 0 to a Int16 value 0.
'    Converted the UInt32 value 121 to a Int16 value 121.
'    Converted the UInt32 value 340 to a Int16 value 340.
'    The UInt32 value 4294967295 is outside the range of the Int16 type.

public:
 static short ToInt16(System::UInt16 value);

public static short ToInt16 (ushort value);

[System.CLSCompliant(false)]
public static short ToInt16 (ushort value);

static member ToInt16 : uint16 -> int16

[<System.CLSCompliant(false)>]
static member ToInt16 : uint16 -> int16

Public Shared Function ToInt16 (value As UShort) As Short

参数

返回

Int16

一个与 value 等效的 16 位带符号整数。A 16-bit signed integer that is equivalent to value.

属性

CLSCompliantAttribute

例外

示例

下面的示例尝试将16位无符号整数数组中的每个元素转换为16位带符号整数。The following example attempts to convert each element in an array of unsigned 16-bit integers to a 16-bit signed integer.

ushort[] numbers = { UInt16.MinValue, 121, 340, UInt16.MaxValue };
short result;
foreach (ushort number in numbers)
{
   try {
      result = Convert.ToInt16(number);
      Console.WriteLine("Converted the {0} value {1} to a {2} value {3}.",
                        number.GetType().Name, number,
                        result.GetType().Name, result);
   }
   catch (OverflowException) {
      Console.WriteLine("The {0} value {1} is outside the range of the Int16 type.",
                        number.GetType().Name, number);
   }
}
// The example displays the following output:
//       Converted the UInt16 value 0 to a Int16 value 0.
//       Converted the UInt16 value 121 to a Int16 value 121.
//       Converted the UInt16 value 340 to a Int16 value 340.
//       The UInt16 value 65535 is outside the range of the Int16 type.

Dim numbers() As UShort = { UInt16.MinValue, 121, 340, UInt16.MaxValue }
Dim result As Short
For Each number As UShort In numbers
   Try
      result = Convert.ToInt16(number)
      Console.WriteLine("Converted the {0} value {1} to a {2} value {3}.", _
                        number.GetType().Name, number, _
                        result.GetType().Name, result)
   Catch e As OverflowException
      Console.WriteLine("The {0} value {1} is outside the range of the Int16 type.", _
                        number.GetType().Name, number)
   End Try
Next
' The example displays the following output:
'       Converted the UInt16 value 0 to a Int16 value 0.
'       Converted the UInt16 value 121 to a Int16 value 121.
'       Converted the UInt16 value 340 to a Int16 value 340.
'       The UInt16 value 65535 is outside the range of the Int16 type.

public:
 static short ToInt16(System::String ^ value);

public static short ToInt16 (string value);

static member ToInt16 : string -> int16

Public Shared Function ToInt16 (value As String) As Short

参数

返回

Int16

一个与 value 中数字等效的 16 位带符号整数，如果 value 为 null，则为 0（零）。A 16-bit signed integer that is equivalent to the number in value, or 0 (zero) if value is null.

例外

示例

下面的示例 ToInt16 使用默认格式设置，用方法转换16位整数的字符串表示形式。The following example converts string representations of 16-bit integers with the ToInt16 method, using default formatting.

// Example of the Convert::ToInt16( String* ) and 
// Convert::ToInt16( String*, IFormatProvider* ) methods.
using namespace System;
using namespace System::Globalization;
const __wchar_t * protoFmt = L"{0,-20}{1,-20}{2}";

// Get the exception type name; remove the namespace prefix.
String^ GetExceptionType( Exception^ ex )
{
   String^ exceptionType = ex->GetType()->ToString();
   return exceptionType->Substring( exceptionType->LastIndexOf( '.' ) + 1 );
}

void ConvertToInt16( String^ numericStr, IFormatProvider^ provider )
{
   Object^ defaultValue;
   Object^ providerValue;
   
   // Convert numericStr to Int16 without a format provider.
   try
   {
      defaultValue = Convert::ToInt16( numericStr );
   }
   catch ( Exception^ ex ) 
   {
      defaultValue = GetExceptionType( ex );
   }

   
   // Convert numericStr to Int16 with a format provider.
   try
   {
      providerValue = Convert::ToInt16( numericStr, provider );
   }
   catch ( Exception^ ex ) 
   {
      providerValue = GetExceptionType( ex );
   }

   Console::WriteLine( gcnew String( protoFmt ), numericStr, defaultValue, providerValue );
}

int main()
{
   
   // Create a NumberFormatInfo object and set several of its
   // properties that apply to numbers.
   NumberFormatInfo^ provider = gcnew NumberFormatInfo;
   
   // These properties affect the conversion.
   provider->NegativeSign = "neg ";
   provider->PositiveSign = "pos ";
   
   // These properties do not affect the conversion.
   // The input string cannot have decimal and group separators.
   provider->NumberDecimalSeparator = ".";
   provider->NumberGroupSeparator = ",";
   array<Int32>^sizes = {3};
   provider->NumberGroupSizes = sizes;
   provider->NumberNegativePattern = 0;
   Console::WriteLine( "This example of\n"
   "  Convert::ToInt16( String* ) and \n"
   "  Convert::ToInt16( String*, IFormatProvider* ) "
   "\ngenerates the following output. It converts "
   "several strings to \nshort values, using "
   "default formatting or a NumberFormatInfo object.\n" );
   Console::WriteLine( gcnew String( protoFmt ), "String to convert", "Default/exception", "Provider/exception" );
   Console::WriteLine( gcnew String( protoFmt ), "-----------------", "-----------------", "------------------" );
   
   // Convert strings, with and without an IFormatProvider.
   ConvertToInt16( "12345", provider );
   ConvertToInt16( "+12345", provider );
   ConvertToInt16( "pos 12345", provider );
   ConvertToInt16( "-12345", provider );
   ConvertToInt16( "neg 12345", provider );
   ConvertToInt16( "12345.", provider );
   ConvertToInt16( "12,345", provider );
   ConvertToInt16( "(12345)", provider );
   ConvertToInt16( "32768", provider );
   ConvertToInt16( "-32769", provider );
}

/*
This example of
  Convert::ToInt16( String* ) and
  Convert::ToInt16( String*, IFormatProvider* )
generates the following output. It converts several strings to
short values, using default formatting or a NumberFormatInfo object.

String to convert   Default/exception   Provider/exception
-----------------   -----------------   ------------------
12345               12345               12345
+12345              12345               FormatException
pos 12345           FormatException     12345
-12345              -12345              FormatException
neg 12345           FormatException     -12345
12345.              FormatException     FormatException
12,345              FormatException     FormatException
(12345)             FormatException     FormatException
32768               OverflowException   OverflowException
-32769              OverflowException   FormatException
*/

// Example of the Convert.ToInt16( string ) and
// Convert.ToInt16( string, IFormatProvider ) methods.
using System;
using System.Globalization;

class ToInt16ProviderDemo
{
    static string format = "{0,-20}{1,-20}{2}";

     // Get the exception type name; remove the namespace prefix.
    static string GetExceptionType( Exception ex )
    {
        string exceptionType = ex.GetType( ).ToString( );
        return exceptionType.Substring(
            exceptionType.LastIndexOf( '.' ) + 1 );
    }

    static void ConvertToInt16( string numericStr,
        IFormatProvider provider )
    {
        object defaultValue;
        object providerValue;

        // Convert numericStr to Int16 without a format provider.
        try
        {
            defaultValue = Convert.ToInt16( numericStr );
        }
        catch( Exception ex )
        {
            defaultValue = GetExceptionType( ex );
        }

        // Convert numericStr to Int16 with a format provider.
        try
        {
            providerValue = Convert.ToInt16( numericStr, provider );
        }
        catch( Exception ex )
        {
            providerValue = GetExceptionType( ex );
        }

        Console.WriteLine( format, numericStr,
            defaultValue, providerValue );
    }

    public static void Main( )
    {
        // Create a NumberFormatInfo object and set several of its
        // properties that apply to numbers.
        NumberFormatInfo provider = new NumberFormatInfo();

        // These properties affect the conversion.
        provider.NegativeSign = "neg ";
        provider.PositiveSign = "pos ";

        // These properties do not affect the conversion.
        // The input string cannot have decimal and group separators.
        provider.NumberDecimalSeparator = ".";
        provider.NumberGroupSeparator = ",";
        provider.NumberGroupSizes = new int[ ] { 3 };
        provider.NumberNegativePattern = 0;

        Console.WriteLine("This example of\n" +
            "  Convert.ToInt16( string ) and \n" +
            "  Convert.ToInt16( string, IFormatProvider ) " +
            "\ngenerates the following output. It converts " +
            "several strings to \nshort values, using " +
            "default formatting or a NumberFormatInfo object.\n" );
        Console.WriteLine( format, "String to convert",
            "Default/exception", "Provider/exception" );
        Console.WriteLine( format, "-----------------",
            "-----------------", "------------------" );

        // Convert strings, with and without an IFormatProvider.
        ConvertToInt16( "12345", provider );
        ConvertToInt16( "+12345", provider );
        ConvertToInt16( "pos 12345", provider );
        ConvertToInt16( "-12345", provider );
        ConvertToInt16( "neg 12345", provider );
        ConvertToInt16( "12345.", provider );
        ConvertToInt16( "12,345", provider );
        ConvertToInt16( "(12345)", provider );
        ConvertToInt16( "32768", provider );
        ConvertToInt16( "-32769", provider );
    }
}

/*
This example of
  Convert.ToInt16( string ) and
  Convert.ToInt16( string, IFormatProvider )
generates the following output. It converts several strings to
short values, using default formatting or a NumberFormatInfo object.

String to convert   Default/exception   Provider/exception
-----------------   -----------------   ------------------
12345               12345               12345
+12345              12345               FormatException
pos 12345           FormatException     12345
-12345              -12345              FormatException
neg 12345           FormatException     -12345
12345.              FormatException     FormatException
12,345              FormatException     FormatException
(12345)             FormatException     FormatException
32768               OverflowException   OverflowException
-32769              OverflowException   FormatException
*/

' Example of the Convert.ToInt16( String ) and 
' Convert.ToInt16( String, IFormatProvider ) methods.
Imports System.Globalization

Module ToInt16ProviderDemo

    Dim format As String = "{0,-20}{1,-20}{2}"

    ' Get the exception type name; remove the namespace prefix.
    Function GetExceptionType( ex As Exception ) As String

        Dim exceptionType   As String = ex.GetType( ).ToString( )
        Return exceptionType.Substring( _
            exceptionType.LastIndexOf( "."c ) + 1 )
    End Function

    Sub ConvertToInt16( numericStr As String, _
        provider As IFormatProvider )

        Dim defaultValue    As Object
        Dim providerValue   As Object

        ' Convert numericStr to Int16 without a format provider.
        Try
            defaultValue = Convert.ToInt16( numericStr )
        Catch ex As Exception
            defaultValue = GetExceptionType( ex )
        End Try

        ' Convert numericStr to Int16 with a format provider.
        Try
            providerValue = Convert.ToInt16( numericStr, provider )
        Catch ex As Exception
            providerValue = GetExceptionType( ex )
        End Try

        Console.WriteLine( format, numericStr, _
            defaultValue, providerValue )
    End Sub

    Sub Main( )

        ' Create a NumberFormatInfo object and set several of its
        ' properties that apply to numbers.
        Dim provider  As NumberFormatInfo = new NumberFormatInfo( )

        ' These properties affect the conversion.
        provider.NegativeSign = "neg "
        provider.PositiveSign = "pos "

        ' These properties do not affect the conversion.
        ' The input string cannot have decimal and group separators.
        provider.NumberDecimalSeparator = "."
        provider.NumberGroupSeparator = ","
        provider.NumberGroupSizes = New Integer( ) { 3 }
        provider.NumberNegativePattern = 0

        Console.WriteLine( "This example of" & vbCrLf & _
            "  Convert.ToInt16( String ) and " & vbCrLf & _
            "  Convert.ToInt16( String, IFormatProvider ) " & _
            vbCrLf & "generates the following output. It " & _
            "converts several strings to " & vbCrLf & "Short " & _
            "values, using default formatting " & _
            "or a NumberFormatInfo object." & vbCrLf )
        Console.WriteLine( format, "String to convert", _
            "Default/exception", "Provider/exception" )
        Console.WriteLine( format, "-----------------", _
            "-----------------", "------------------" )

        ' Convert strings, with and without an IFormatProvider.
        ConvertToInt16( "12345", provider )
        ConvertToInt16( "+12345", provider )
        ConvertToInt16( "pos 12345", provider )
        ConvertToInt16( "-12345", provider )
        ConvertToInt16( "neg 12345", provider )
        ConvertToInt16( "12345.", provider )
        ConvertToInt16( "12,345", provider )
        ConvertToInt16( "(12345)", provider )
        ConvertToInt16( "32768", provider )
        ConvertToInt16( "-32769", provider )
    End Sub 
End Module 

' This example of
'   Convert.ToInt16( String ) and
'   Convert.ToInt16( String, IFormatProvider )
' generates the following output. It converts several strings to
' Short values, using default formatting or a NumberFormatInfo object.
' 
' String to convert   Default/exception   Provider/exception
' -----------------   -----------------   ------------------
' 12345               12345               12345
' +12345              12345               FormatException
' pos 12345           FormatException     12345
' -12345              -12345              FormatException
' neg 12345           FormatException     -12345
' 12345.              FormatException     FormatException
' 12,345              FormatException     FormatException
' (12345)             FormatException     FormatException
' 32768               OverflowException   OverflowException
' -32769              OverflowException   FormatException

注解

使用 ToInt16(String) 方法等效于传递 value 到 Int16.Parse(String) 方法。Using the ToInt16(String) method is equivalent to passing value to the Int16.Parse(String) method. 使用当前线程区域性的格式设置约定解释 value。value is interpreted by using the formatting conventions of the current thread culture.

如果你不希望在转换失败时处理异常，则可以改为调用 Int16.TryParse 方法。If you prefer not to handle an exception if the conversion fails, you can call the Int16.TryParse method instead. 它将返回一个 Boolean 值，该值指示转换是成功还是失败。It returns a Boolean value that indicates whether the conversion succeeded or failed.

另请参阅

• Parse(String)

public:
 static short ToInt16(float value);

public static short ToInt16 (float value);

static member ToInt16 : single -> int16

Public Shared Function ToInt16 (value As Single) As Short

参数

返回

Int16

value，舍入为最接近的 16 位带符号整数。value, rounded to the nearest 16-bit signed integer. 如果 value 为两个整数中间的数字，则返回二者中的偶数；即 4.5 转换为 4，而 5.5 转换为 6。If value is halfway between two whole numbers, the even number is returned; that is, 4.5 is converted to 4, and 5.5 is converted to 6.

例外

示例

下面的示例尝试将值数组中的每个元素转换 Single 为16位带符号整数。The following example attempts to convert each element in an array of Single values to a 16-bit signed integer.

float[] values = { Single.MinValue, -1.38e10f, -1023.299f, -12.98f,
                   0f, 9.113e-16f, 103.919f, 17834.191f, Single.MaxValue };
short result;

foreach (float value in values)
{
   try {
      result = Convert.ToInt16(value);
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.",
                        value.GetType().Name, value, result.GetType().Name, result);
   }
   catch (OverflowException) {
      Console.WriteLine("{0} is outside the range of the Int16 type.", value);
   }
}
// The example displays the following output:
//    -3.40282346638529E+38 is outside the range of the Int16 type.
//    -13799999488 is outside the range of the Int16 type.
//    Converted the Double value -1023.29901123047 to the Int16 value -1023.
//    Converted the Double value -12.9799995422363 to the Int16 value -13.
//    Converted the Double value 0 to the Int16 value 0.
//    Converted the Double value 9.11299983940444E-16 to the Int16 value 0.
//    Converted the Double value 103.918998718262 to the Int16 value 104.
//    Converted the Double value 17834.19140625 to the Int16 value 17834.
//    3.40282346638529E+38 is outside the range of the Int16 type.

Dim values() As Single = { Single.MinValue, -1.38e10, -1023.299, -12.98, _
                           0, 9.113e-16, 103.919, 17834.191, Single.MaxValue }
Dim result As Short

For Each value As Single In values
   Try
      result = Convert.ToInt16(value)
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.", _
                        value.GetType().Name, value, result.GetType().Name, result)
   Catch e As OverflowException
      Console.WriteLine("{0} is outside the range of the Int16 type.", value)
   End Try   
Next                                 
' The example displays the following output:
'    -3.40282346638529E+38 is outside the range of the Int16 type.
'    -13799999488 is outside the range of the Int16 type.
'    Converted the Double value -1023.29901123047 to the Int16 value -1023.
'    Converted the Double value -12.9799995422363 to the Int16 value -13.
'    Converted the Double value 0 to the Int16 value 0.
'    Converted the Double value 9.11299983940444E-16 to the Int16 value 0.
'    Converted the Double value 103.918998718262 to the Int16 value 104.
'    Converted the Double value 17834.19140625 to the Int16 value 17834.
'    3.40282346638529E+38 is outside the range of the Int16 type.

另请参阅

• Single
• Round

public:
 static short ToInt16(System::SByte value);

public static short ToInt16 (sbyte value);

[System.CLSCompliant(false)]
public static short ToInt16 (sbyte value);

static member ToInt16 : sbyte -> int16

[<System.CLSCompliant(false)>]
static member ToInt16 : sbyte -> int16

Public Shared Function ToInt16 (value As SByte) As Short

参数

返回

Int16

一个与 value 等效的 8 位带符号整数。A 8-bit signed integer that is equivalent to value.

属性

CLSCompliantAttribute

示例

下面的示例将具有符号字节的数组中的每个元素转换为16位带符号整数。The following example converts each element in an array of signed bytes to a 16-bit signed integer.

sbyte[] numbers = { SByte.MinValue, -1, 0, 10, SByte.MaxValue };
short result;

foreach (sbyte number in numbers)
{
   result = Convert.ToInt16(number);
   Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.",
                     number.GetType().Name, number,
                     result.GetType().Name, result);
}
// The example displays the following output:
//       Converted the SByte value -128 to the Int16 value -128.
//       Converted the SByte value -1 to the Int16 value -1.
//       Converted the SByte value 0 to the Int16 value 0.
//       Converted the SByte value 10 to the Int16 value 10.
//       Converted the SByte value 127 to the Int16 value 127.

Dim numbers() As SByte = { SByte.MinValue, -1, 0, 10, SByte.MaxValue }
Dim result As Short

For Each number As SByte In numbers
   result = Convert.ToInt16(number)
   Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.", _
                     number.GetType().Name, number, _
                     result.GetType().Name, result)
Next
' The example displays the following output:
'       Converted the SByte value -128 to the Int16 value -128.
'       Converted the SByte value -1 to the Int16 value -1.
'       Converted the SByte value 0 to the Int16 value 0.
'       Converted the SByte value 10 to the Int16 value 10.
'       Converted the SByte value 127 to the Int16 value 127.

public:
 static short ToInt16(int value);

public static short ToInt16 (int value);

static member ToInt16 : int -> int16

Public Shared Function ToInt16 (value As Integer) As Short

参数

返回

Int16

与 value 等效的 16 位带符号整数。The 16-bit signed integer equivalent of value.

例外

示例

下面的示例尝试将整数数组中的每个元素转换为16位带符号整数。The following example attempts to convert each element in an array of integers to a 16-bit signed integer.

int[] numbers = { Int32.MinValue, -1, 0, 121, 340, Int32.MaxValue };
short result;

foreach (int number in numbers)
{
   try {
      result = Convert.ToInt16(number);
      Console.WriteLine("Converted the {0} value {1} to a {2} value {3}.",
                        number.GetType().Name, number,
                        result.GetType().Name, result);
   }
   catch (OverflowException) {
      Console.WriteLine("The {0} value {1} is outside the range of the Int16 type.",
                        number.GetType().Name, number);
   }
}
// The example displays the following output:
//    The Int32 value -2147483648 is outside the range of the Int16 type.
//    Converted the Int32 value -1 to a Int16 value -1.
//    Converted the Int32 value 0 to a Int16 value 0.
//    Converted the Int32 value 121 to a Int16 value 121.
//    Converted the Int32 value 340 to a Int16 value 340.
//    The Int32 value 2147483647 is outside the range of the Int16 type.

Dim numbers() As Integer = { Int32.MinValue, -1, 0, 121, 340, Int32.MaxValue }
Dim result As Short

For Each number As Integer In numbers
   Try
      result = Convert.ToInt16(number)
      Console.WriteLine("Converted the {0} value {1} to a {2} value {3}.", _
                        number.GetType().Name, number, _
                        result.GetType().Name, result)
   Catch e As OverflowException
      Console.WriteLine("The {0} value {1} is outside the range of the Int16 type.", _
                        number.GetType().Name, number)
   End Try
Next
' The example displays the following output:
'    The Int32 value -2147483648 is outside the range of the Int16 type.
'    Converted the Int32 value -1 to a Int16 value -1.
'    Converted the Int32 value 0 to a Int16 value 0.
'    Converted the Int32 value 121 to a Int16 value 121.
'    Converted the Int32 value 340 to a Int16 value 340.
'    The Int32 value 2147483647 is outside the range of the Int16 type.

public:
 static short ToInt16(long value);

public static short ToInt16 (long value);

static member ToInt16 : int64 -> int16

Public Shared Function ToInt16 (value As Long) As Short

参数

返回

Int16

一个与 value 等效的 16 位带符号整数。A 16-bit signed integer that is equivalent to value.

例外

示例

下面的示例尝试将长整数数组中的每个元素转换为16位带符号整数。The following example attempts to convert each element in an array of long integers to a 16-bit signed integer.

long[] numbers = { Int64.MinValue, -1, 0, 121, 340, Int64.MaxValue };
short result;

foreach (long number in numbers)
{
   try {
      result = Convert.ToInt16(number);
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.",
                        number.GetType().Name, number,
                        result.GetType().Name, result);
   }
   catch (OverflowException) {
      Console.WriteLine("The {0} value {1} is outside the range of the Int16 type.",
                        number.GetType().Name, number);
   }
}
// The example displays the following output:
//    The Int64 value -9223372036854775808 is outside the range of the Int16 type.
//    Converted the Int64 value -1 to the Int16 value -1.
//    Converted the Int64 value 0 to the Int16 value 0.
//    Converted the Int64 value 121 to the Int16 value 121.
//    Converted the Int64 value 340 to the Int16 value 340.
//    The Int64 value 9223372036854775807 is outside the range of the Int16 type.

Dim numbers() As Long = { Int64.MinValue, -1, 0, 121, 340, Int64.MaxValue }
Dim result As Short
For Each number As Long In numbers
   Try
      result = Convert.ToInt16(number)
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.", _
                        number.GetType().Name, number, _
                        result.GetType().Name, result)
   Catch e As OverflowException
      Console.WriteLine("The {0} value {1} is outside the range of the Int16 type.", _
                        number.GetType().Name, number)
   End Try
Next
' The example displays the following output:
'    The Int64 value -9223372036854775808 is outside the range of the Int16 type.
'    Converted the Int64 value -1 to the Int16 value -1.
'    Converted the Int64 value 0 to the Int16 value 0.
'    Converted the Int64 value 121 to the Int16 value 121.
'    Converted the Int64 value 340 to the Int16 value 340.
'    The Int64 value 9223372036854775807 is outside the range of the Int16 type.

public:
 static short ToInt16(short value);

public static short ToInt16 (short value);

static member ToInt16 : int16 -> int16

Public Shared Function ToInt16 (value As Short) As Short

参数

返回

Int16

不经更改即返回 value。value is returned unchanged.

public:
 static short ToInt16(double value);

public static short ToInt16 (double value);

static member ToInt16 : double -> int16

Public Shared Function ToInt16 (value As Double) As Short

参数

返回

Int16

value，舍入为最接近的 16 位带符号整数。value, rounded to the nearest 16-bit signed integer. 如果 value 为两个整数中间的数字，则返回二者中的偶数；即 4.5 转换为 4，而 5.5 转换为 6。If value is halfway between two whole numbers, the even number is returned; that is, 4.5 is converted to 4, and 5.5 is converted to 6.

例外

示例

下面的示例将值数组中的每个元素转换 Double 为16位带符号整数。The following example converts each element in an array of Double values to a 16-bit signed integer. 该示例说明了在 Double 执行转换之前，将舍入值的任何小数部分。The example illustrates that any fractional part of a Double value is rounded before performing the conversion.

double[] values = { Double.MinValue, -1.38e10, -1023.299, -12.98,
                    0, 9.113e-16, 103.919, 17834.191, Double.MaxValue };
short result;

foreach (double value in values)
{
   try {
      result = Convert.ToInt16(value);
      Console.WriteLine("Converted {0} to {1}.", value, result);
   }
   catch (OverflowException)
   {
      Console.WriteLine("{0} is outside the range of the Int16 type.", value);
   }
}
//       -1.79769313486232E+308 is outside the range of the Int16 type.
//       -13800000000 is outside the range of the Int16 type.
//       Converted -1023.299 to -1023.
//       Converted -12.98 to -13.
//       Converted 0 to 0.
//       Converted 9.113E-16 to 0.
//       Converted 103.919 to 104.
//       Converted 17834.191 to 17834.
//       1.79769313486232E+308 is outside the range of the Int16 type.

Dim values() As Double = { Double.MinValue, -1.38e10, -1023.299, -12.98, _
                           0, 9.113e-16, 103.919, 17834.191, Double.MaxValue }
Dim result As Short

For Each value As Double In values
   Try
      result = Convert.ToInt16(value)
      Console.WriteLine("Converted {0} to {1}.", value, result)
   Catch e As OverflowException
      Console.WriteLine("{0} is outside the range of the Int16 type.", value)
   End Try   
Next                                 
'       -1.79769313486232E+308 is outside the range of the Int16 type.
'       -13800000000 is outside the range of the Int16 type.
'       Converted -1023.299 to -1023.
'       Converted -12.98 to -13.
'       Converted 0 to 0.
'       Converted 9.113E-16 to 0.
'       Converted 103.919 to 104.
'       Converted 17834.191 to 17834.
'       1.79769313486232E+308 is outside the range of the Int16 type.

另请参阅

• Double
• Round

public:
 static short ToInt16(System::Decimal value);

public static short ToInt16 (decimal value);

static member ToInt16 : decimal -> int16

Public Shared Function ToInt16 (value As Decimal) As Short

参数

返回

Int16

value，舍入为最接近的 16 位带符号整数。value, rounded to the nearest 16-bit signed integer. 如果 value 为两个整数中间的数字，则返回二者中的偶数；即 4.5 转换为 4，而 5.5 转换为 6。If value is halfway between two whole numbers, the even number is returned; that is, 4.5 is converted to 4, and 5.5 is converted to 6.

例外

示例

下面的示例尝试将值数组中的每个元素转换 Decimal 为16位带符号整数。The following example attempts to convert each element in an array of Decimal values to a 16-bit signed integer. 该示例说明了 Decimal 在执行转换时，将舍入值的任何小数部分。The example illustrates that any fractional part of a Decimal value is rounded when performing the conversion.

decimal[] values = { Decimal.MinValue, -1034.23m, -12m, 0m, 147m,
                            9214.16m, Decimal.MaxValue };
short result;

foreach (decimal value in values)
{
   try {
      result = Convert.ToInt16(value);
      Console.WriteLine("Converted {0} to {1}.", value, result);
   }
   catch (OverflowException)
   {
      Console.WriteLine("{0} is outside the range of the Int16 type.",
                        value);
   }
}
// The example displays the following output:
//    -79228162514264337593543950335 is outside the range of the Int16 type.
//    Converted -1034.23 to -1034.
//    Converted -12 to -12.
//    Converted 0 to 0.
//    Converted 147 to 147.
//    Converted 9214.16 to 9214.
//    79228162514264337593543950335 is outside the range of the Int16 type.

Dim values() As Decimal = { Decimal.MinValue, -1034.23d, -12d, 0d, 147d, _
                            9214.16d, Decimal.MaxValue }
Dim result As Short

For Each value As Decimal In values
   Try
      result = Convert.ToInt16(value)
      Console.WriteLine("Converted {0} to {1}.", value, result)
   Catch e As OverflowException
      Console.WriteLine("{0} is outside the range of the Int16 type.", _
                        value)
   End Try   
Next                                  
' The example displays the following output:
'    -79228162514264337593543950335 is outside the range of the Int16 type.
'    Converted -1034.23 to -1034.
'    Converted -12 to -12.
'    Converted 0 to 0.
'    Converted 147 to 147.
'    Converted 9214.16 to 9214.
'    79228162514264337593543950335 is outside the range of the Int16 type.

另请参阅

• Round

public:
 static short ToInt16(DateTime value);

public static short ToInt16 (DateTime value);

static member ToInt16 : DateTime -> int16

Public Shared Function ToInt16 (value As DateTime) As Short

参数

返回

Int16

不支持此转换。This conversion is not supported. 不返回任何值。No value is returned.

例外

public:
 static short ToInt16(char value);

public static short ToInt16 (char value);

static member ToInt16 : char -> int16

Public Shared Function ToInt16 (value As Char) As Short

参数

返回

Int16

一个与 value 等效的 16 位带符号整数。A 16-bit signed integer that is equivalent to value.

例外

示例

下面的示例尝试将值数组中的每个元素转换 Char 为16位带符号整数。The following example attempts to convert each element in an array of Char values to a 16-bit signed integer.

char[] chars = { 'a', 'z', '\x0007', '\x03FF',
                 '\x7FFF', '\xFFFE' };
short result;

foreach (char ch in chars)
{
   try {
      result = Convert.ToInt16(ch);
      Console.WriteLine("'{0}' converts to {1}.", ch, result);
   }
   catch (OverflowException) {
      Console.WriteLine("Unable to convert u+{0} to an Int16.",
                        ((int)ch).ToString("X4"));
   }
}
// The example displays the following output:
//       'a' converts to 97.
//       'z' converts to 122.
//       '' converts to 7.
//       '?' converts to 1023.
//       '?' converts to 32767.
//       Unable to convert u+FFFE to a UInt16.

Dim chars() As Char = { "a"c, "z"c, ChrW(7), ChrW(1023), _
                        ChrW(Short.MaxValue), ChrW(&hFFFE) }
Dim result As Short
                        
For Each ch As Char in chars
   Try
      result = Convert.ToInt16(ch)
      Console.WriteLine("'{0}' converts to {1}.", ch, result)
   Catch e As OverflowException
      Console.WriteLine("Unable to convert u+{0} to an Int16.", _
                        AscW(ch).ToString("X4"))
   End Try
Next   
' The example displays the following output:
'       'a' converts to 97.
'       'z' converts to 122.
'       '' converts to 7.
'       '?' converts to 1023.
'       '?' converts to 32767.
'       Unable to convert u+FFFE to a UInt16.

public:
 static short ToInt16(System::Byte value);

public static short ToInt16 (byte value);

static member ToInt16 : byte -> int16

Public Shared Function ToInt16 (value As Byte) As Short

参数

返回

Int16

一个与 value 等效的 16 位带符号整数。A 16-bit signed integer that is equivalent to value.

示例

下面的示例将值数组中的每个元素转换 Byte 为16位带符号整数。The following example converts each element in an array of Byte values to a 16-bit signed integer.

byte[] bytes = { Byte.MinValue, 14, 122, Byte.MaxValue};
short result;

foreach (byte byteValue in bytes)
{
   result = Convert.ToInt16(byteValue);
   Console.WriteLine("The Byte value {0} converts to {1}.",
                     byteValue, result);
}
// The example displays the following output:
//       The Byte value 0 converts to 0.
//       The Byte value 14 converts to 14.
//       The Byte value 122 converts to 122.
//       The Byte value 255 converts to 255.

Dim bytes() As Byte = { Byte.MinValue, 14, 122, Byte.MaxValue}
Dim result As Short

For Each byteValue As Byte In bytes
   result = Convert.ToInt16(byteValue)
   Console.WriteLine("The Byte value {0} converts to {1}.", _
                     byteValue, result)
Next
' The example displays the following output:
'       The Byte value 0 converts to 0.
'       The Byte value 14 converts to 14.
'       The Byte value 122 converts to 122.
'       The Byte value 255 converts to 255.

public:
 static short ToInt16(bool value);

public static short ToInt16 (bool value);

static member ToInt16 : bool -> int16

Public Shared Function ToInt16 (value As Boolean) As Short

参数

返回

Int16

如果 value 为 true，则为数字 1；否则，为 0。The number 1 if value is true; otherwise, 0.

示例

下面的示例将布尔值 true 和 false 值转换为 Int16 值。The following example converts the Boolean values true and false to Int16 values.

bool falseFlag = false;
bool trueFlag = true;

Console.WriteLine("{0} converts to {1}.", falseFlag,
                  Convert.ToInt16(falseFlag));
Console.WriteLine("{0} converts to {1}.", trueFlag,
                  Convert.ToInt16(trueFlag));
// The example displays the following output:
//       False converts to 0.
//       True converts to 1.

Dim falseFlag As Boolean = False
Dim trueFlag As Boolean = True

Console.WriteLine("{0} converts to {1}.", falseFlag, _
                  Convert.ToInt16(falseFlag))
Console.WriteLine("{0} converts to {1}.", trueFlag, _
                  Convert.ToInt16(trueFlag))
' The example displays the following output:
'       False converts to 0.
'       True converts to 1.

public:
 static short ToInt16(System::Object ^ value);

public static short ToInt16 (object value);

static member ToInt16 : obj -> int16

Public Shared Function ToInt16 (value As Object) As Short

参数

返回

Int16

一个与 value 等效的 16 位带符号整数，如果 value 为 null，则为零。A 16-bit signed integer that is equivalent to value, or zero if value is null.

例外

示例

下面的示例尝试将对象数组中的每个元素转换为16位带符号整数。The following example attempts to convert each element in an object array to a 16-bit signed integer.

object[] values= { true, -12, 163, 935, 'x', new DateTime(2009, 5, 12),
                   "104", "103.0", "-1", "1.00e2", "One", 1.00e2};
short result;

foreach (object value in values)
{
   try {
      result = Convert.ToInt16(value);
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.",
                        value.GetType().Name, value,
                        result.GetType().Name, result);
   }
   catch (OverflowException) {
      Console.WriteLine("The {0} value {1} is outside the range of the Int16 type.",
                        value.GetType().Name, value);
   }
   catch (FormatException) {
      Console.WriteLine("The {0} value {1} is not in a recognizable format.",
                        value.GetType().Name, value);
   }
   catch (InvalidCastException) {
      Console.WriteLine("No conversion to an Int16 exists for the {0} value {1}.",
                        value.GetType().Name, value);
   }
}
// The example displays the following output:
//    Converted the Boolean value True to the Int16 value 1.
//    Converted the Int32 value -12 to the Int16 value -12.
//    Converted the Int32 value 163 to the Int16 value 163.
//    Converted the Int32 value 935 to the Int16 value 935.
//    Converted the Char value x to the Int16 value 120.
//    No conversion to an Int16 exists for the DateTime value 5/12/2009 12:00:00 AM.
//    Converted the String value 104 to the Int16 value 104.
//    The String value 103.0 is not in a recognizable format.
//    Converted the String value -1 to the Int16 value -1.
//    The String value 1.00e2 is not in a recognizable format.
//    The String value One is not in a recognizable format.
//    Converted the Double value 100 to the Int16 value 100.

Dim values() As Object = { True, -12, 163, 935, "x"c, #5/12/2009#, _
                           "104", "103.0", "-1", _
                           "1.00e2", "One", 1.00e2}
Dim result As Short

For Each value As Object In values
   Try
      result = Convert.ToInt16(value)
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.", _
                        value.GetType().Name, value, _
                        result.GetType().Name, result)
   Catch e As OverflowException
      Console.WriteLine("The {0} value {1} is outside the range of the Int16 type.", _
                        value.GetType().Name, value)
   Catch e As FormatException
      Console.WriteLine("The {0} value {1} is not in a recognizable format.", _
                        value.GetType().Name, value)
   Catch e As InvalidCastException
      Console.WriteLine("No conversion to an Int16 exists for the {0} value {1}.", _
                        value.GetType().Name, value)
                        
   End Try
Next                           
' The example displays the following output:
'    Converted the Boolean value True to the Int16 value 1.
'    Converted the Int32 value -12 to the Int16 value -12.
'    Converted the Int32 value 163 to the Int16 value 163.
'    Converted the Int32 value 935 to the Int16 value 935.
'    Converted the Char value x to the Int16 value 120.
'    No conversion to an Int16 exists for the DateTime value 5/12/2009 12:00:00 AM.
'    Converted the String value 104 to the Int16 value 104.
'    The String value 103.0 is not in a recognizable format.
'    Converted the String value -1 to the Int16 value -1.
'    The String value 1.00e2 is not in a recognizable format.
'    The String value One is not in a recognizable format.
'    Converted the Double value 100 to the Int16 value 100.

注解

如果不 value 为 null ，则此方法包装对的 IConvertible.ToInt16 基础类型的实现的调用 value 。If value is not null, this method wraps a call to the IConvertible.ToInt16 implementation of the underlying type of value.