Convert.ToSByte 方法

定义

将指定的值转换为 8 位有符号整数。Converts a specified value to an 8-bit signed integer.

重载

ToSByte(SByte)

返回指定的 8 位有符号整数;不执行实际的转换。Returns the specified 8-bit signed integer; no actual conversion is performed.

ToSByte(String, Int32)

将指定基数的数字的字符串表示形式转换为等效的 8 位有符号整数。Converts the string representation of a number in a specified base to an equivalent 8-bit signed integer.

ToSByte(String, IFormatProvider)

使用指定的区域性特定格式设置信息,将数字的指定字符串表示形式转换为等效的 8 位带符号整数。Converts the specified string representation of a number to an equivalent 8-bit signed integer, using the specified culture-specific formatting information.

ToSByte(Object, IFormatProvider)

使用指定的区域性特定格式信息,将指定对象的值转换为 8 位带符号整数。Converts the value of the specified object to an 8-bit signed integer, using the specified culture-specific formatting information.

ToSByte(UInt64)

将指定的 64 位无符号整数的值转换为等效的 8 位有符号整数。Converts the value of the specified 64-bit unsigned integer to an equivalent 8-bit signed integer.

ToSByte(UInt32)

将指定的 32 位无符号整数的值转换为等效的 8 位有符号整数。Converts the value of the specified 32-bit unsigned integer to an equivalent 8-bit signed integer.

ToSByte(String)

将数字的指定字符串表示形式转换为等效的 8 位带符号整数。Converts the specified string representation of a number to an equivalent 8-bit signed integer.

ToSByte(Single)

将指定的单精度浮点数的值转换为等效的 8 位带符号整数。Converts the value of the specified single-precision floating-point number to an equivalent 8-bit signed integer.

ToSByte(Object)

将指定对象的值转换为 8 位带符号整数。Converts the value of the specified object to an 8-bit signed integer.

ToSByte(UInt16)

将指定的 16 位无符号整数的值转换为等效的 8 位有符号整数。Converts the value of the specified 16-bit unsigned integer to the equivalent 8-bit signed integer.

ToSByte(Int32)

将指定的 32 位有符号整数的值转换为等效的 8 位有符号整数。Converts the value of the specified 32-bit signed integer to an equivalent 8-bit signed integer.

ToSByte(Int64)

将指定的 64 位有符号整数的值转换为等效的 8 位有符号整数。Converts the value of the specified 64-bit signed integer to an equivalent 8-bit signed integer.

ToSByte(Byte)

将指定的 8 位无符号整数的值转换为等效的 8 位有符号整数。Converts the value of the specified 8-bit unsigned integer to the equivalent 8-bit signed integer.

ToSByte(Char)

将指定的 Unicode 字符的值转换为等效的 8 位有符号整数。Converts the value of the specified Unicode character to the equivalent 8-bit signed integer.

ToSByte(DateTime)

调用此方法始终引发 InvalidCastExceptionCalling this method always throws InvalidCastException.

ToSByte(Boolean)

将指定的布尔值转换为等效的 8 位带符号整数。Converts the specified Boolean value to the equivalent 8-bit signed integer.

ToSByte(Double)

将指定的双精度浮点数的值转换为等效的 8 位带符号整数。Converts the value of the specified double-precision floating-point number to an equivalent 8-bit signed integer.

ToSByte(Int16)

将指定的 16 位带符号整数的值转换为等效的 8 位带符号整数。Converts the value of the specified 16-bit signed integer to the equivalent 8-bit signed integer.

ToSByte(Decimal)

将指定的十进制数的值转换为等效的 8 位带符号整数。Converts the value of the specified decimal number to an equivalent 8-bit signed integer.

ToSByte(SByte)

重要

此 API 不符合 CLS。

返回指定的 8 位有符号整数;不执行实际的转换。Returns the specified 8-bit signed integer; no actual conversion is performed.

public:
 static System::SByte ToSByte(System::SByte value);
[System.CLSCompliant(false)]
public static sbyte ToSByte (sbyte value);
static member ToSByte : sbyte -> sbyte
Public Shared Function ToSByte (value As SByte) As SByte

参数

value
SByte

要转换的 8 位无符号整数。The 8-bit signed integer to return.

返回

不经更改即返回 valuevalue is returned unchanged.

属性

ToSByte(String, Int32)

重要

此 API 不符合 CLS。

将指定基数的数字的字符串表示形式转换为等效的 8 位有符号整数。Converts the string representation of a number in a specified base to an equivalent 8-bit signed integer.

public:
 static System::SByte ToSByte(System::String ^ value, int fromBase);
[System.CLSCompliant(false)]
public static sbyte ToSByte (string value, int fromBase);
static member ToSByte : string * int -> sbyte
Public Shared Function ToSByte (value As String, fromBase As Integer) As SByte

参数

value
String

包含要转换的数字的字符串。A string that contains the number to convert.

fromBase
Int32

value 中数字的基数,它必须是 2、8、10 或 16。The base of the number in value, which must be 2, 8, 10, or 16.

返回

value 中数字等效的 8 位带符号整数,如果 valuenull,则为 0(零)。An 8-bit signed integer that is equivalent to the number in value, or 0 (zero) if value is null.

属性

异常

fromBase 不是 2、8、10 或 16。fromBase is not 2, 8, 10, or 16.

- 或 --or- value(表示基数不为 10 的符号数字)的前缀为负号。value, which represents a non-base 10 signed number, is prefixed with a negative sign.

valueEmptyvalue is Empty.

value 包含一个字符,该字符不是由 fromBase 指定的基数中的有效数字。value contains a character that is not a valid digit in the base specified by fromBase. 如果 value 中的第一个字符无效,则该异常消息指示没有要转换的数字;否则,该消息指示 value 包含无效的尾随字符。The exception message indicates that there are no digits to convert if the first character in value is invalid; otherwise, the message indicates that value contains invalid trailing characters.

value(表示基数不为 10 的符号数字)的前缀为负号。value, which represents a non-base 10 signed number, is prefixed with a negative sign.

- 或 --or- value 表示一个小于 MinValue 或大于 MaxValue 的数字。value represents a number that is less than MinValue or greater than MaxValue.

示例

下面的示例尝试将字符串数组中的元素解释为数字值的二进制、八进制和十六进制表示形式,以便将它们转换为无符号字节。The following example attempts to interpret the elements in a string array as the binary, octal, and hexadecimal representation of numeric values in order to convert them to unsigned bytes.

using System;

public class Example
{
   public static void Main()
   {
      int[] baseValues = { 2, 8, 16};
      string[] values = { "FF", "81", "03", "11", "8F", "01", "1C", "111", 
                          "123", "18A" }; 
   
      // Convert to each supported base.
      foreach (int baseValue in baseValues)
      {
         Console.WriteLine("Converting strings in base {0}:", baseValue);
         foreach (string value in values)
         {
            Console.Write("   '{0,-5}  -->  ", value + "'");
            try {
               Console.WriteLine(Convert.ToSByte(value, baseValue));
            }   
            catch (FormatException) {
               Console.WriteLine("Bad Format");
            }   
            catch (OverflowException) {
               Console.WriteLine("Out of Range");
            }
         }
         Console.WriteLine();
      }
   }
}
// The example displays the following output:
//       Converting strings in base 2:
//          'FF'    -->  Bad Format
//          '81'    -->  Bad Format
//          '03'    -->  Bad Format
//          '11'    -->  3
//          '8F'    -->  Bad Format
//          '01'    -->  1
//          '1C'    -->  Bad Format
//          '111'   -->  7
//          '123'   -->  Bad Format
//          '18A'   -->  Bad Format
//       
//       Converting strings in base 8:
//          'FF'    -->  Bad Format
//          '81'    -->  Bad Format
//          '03'    -->  3
//          '11'    -->  9
//          '8F'    -->  Bad Format
//          '01'    -->  1
//          '1C'    -->  Bad Format
//          '111'   -->  73
//          '123'   -->  83
//          '18A'   -->  Bad Format
//       
//       Converting strings in base 16:
//          'FF'    -->  -1
//          '81'    -->  -127
//          '03'    -->  3
//          '11'    -->  17
//          '8F'    -->  -113
//          '01'    -->  1
//          '1C'    -->  28
//          '111'   -->  Out of Range
//          '123'   -->  Out of Range
//          '18A'   -->  Out of Range
Module Example
   Public Sub Main()
      Dim bases() As Integer = { 2, 8, 16}
      Dim values() As String = { "FF", "81", "03", "11", "8F", "01", "1C", _ 
                                 "111", "123", "18A" } 
   
      ' Convert to each supported base.
      For Each base As Integer In bases
         Console.WriteLine("Converting strings in base {0}:", base)
         For Each value As String In values
            Console.Write("   '{0,-5}  -->  ", value + "'")
            Try
               Console.WriteLine(Convert.ToSByte(value, base))
            Catch e As FormatException
               Console.WriteLine("Bad Format")
            Catch e As OverflowException
               Console.WriteLine("Out of Range")
            End Try   
         Next
         Console.WriteLine()
      Next
   End Sub
End Module
' The example displays the following output:
'       Converting strings in base 2:
'          'FF'    -->  Bad Format
'          '81'    -->  Bad Format
'          '03'    -->  Bad Format
'          '11'    -->  3
'          '8F'    -->  Bad Format
'          '01'    -->  1
'          '1C'    -->  Bad Format
'          '111'   -->  7
'          '123'   -->  Bad Format
'          '18A'   -->  Bad Format
'       
'       Converting strings in base 8:
'          'FF'    -->  Bad Format
'          '81'    -->  Bad Format
'          '03'    -->  3
'          '11'    -->  9
'          '8F'    -->  Bad Format
'          '01'    -->  1
'          '1C'    -->  Bad Format
'          '111'   -->  73
'          '123'   -->  83
'          '18A'   -->  Bad Format
'       
'       Converting strings in base 16:
'          'FF'    -->  -1
'          '81'    -->  -127
'          '03'    -->  3
'          '11'    -->  17
'          '8F'    -->  -113
'          '01'    -->  1
'          '1C'    -->  28
'          '111'   -->  Out of Range
'          '123'   -->  Out of Range
'          '18A'   -->  Out of Range

注解

如果 fromBase 为16,则可以使用 "0x" 或 "0X" 作为 value 参数指定的数字的前缀。If fromBase is 16, you can prefix the number specified by the value parameter with "0x" or "0X".

由于非 base 10 数值表示形式不支持负号,因此 ToSByte(String, Int32) 方法假设负数使用两个的补数表示形式。Because the negative sign is not supported for non-base 10 numeric representations, the ToSByte(String, Int32) method assumes that negative numbers use two's complement representation. 换言之,该方法始终将字节(第7)的高序位解释为其符号位。In other words, the method always interprets the high-order bit of a byte (bit 7) as its sign bit. 因此,可以编写代码,在此代码中,如果不是由方法引发异常,则将不在 SByte 数据类型范围内的非基数10的数字转换为 SByte 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 SByte data type is converted to an SByte value without the method throwing an exception. 下面的示例将 MaxValue 转换为其十六进制字符串表示形式,然后调用 ToSByte(String, Int32) 方法。The following example converts MaxValue to its hexadecimal string representation, and then calls the ToSByte(String, Int32) method. 方法会显示消息 "0xff 转换为-1",而不是引发异常。Instead of throwing an exception, the method displays the message, "0xff converts to -1."

// Create a hexadecimal value out of range of the SByte type.
string value = Convert.ToString(byte.MaxValue, 16);
// Convert it back to a number.
try
{
   sbyte number = Convert.ToSByte(value, 16);
   Console.WriteLine("0x{0} converts to {1}.", value, number);
}   
catch (OverflowException)
{
   Console.WriteLine("Unable to convert '0x{0}' to a signed byte.", value);
}   
' Create a hexadecimal value out of range of the SByte type.
Dim value As String = Convert.ToString(Byte.MaxValue, 16)
' Convert it back to a number.
Try
   Dim number As SByte = Convert.ToSByte(value, 16)
   Console.WriteLine("0x{0} converts to {1}.", value, number)
Catch e As OverflowException
   Console.WriteLine("Unable to convert '0x{0}' to a signed byte.", 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,你可以通过在将值转换为其十六进制字符串表示形式之前,通过确定值是否表示无符号或带符号类型,来确保方法正确地处理溢出。As the following example illustrates, you can ensure that the method handles overflows appropriately by first determining whether a value represents an unsigned or a signed type when converting it to its hexadecimal string representation. 如果原始值是无符号类型,但转换回带符号字节的转换将生成一个符号位为的值,则将引发异常。Throw an exception if the original value was an unsigned type but the conversion back to a signed byte yields a value whose sign bit is on.

// Create a hexadecimal value out of range of the SByte type.
byte sourceNumber = byte.MaxValue;
bool isSigned = Math.Sign(Convert.ToDouble(sourceNumber.GetType().GetField("MinValue").GetValue(null))) == -1;
string value = Convert.ToString(sourceNumber, 16);
sbyte targetNumber;
try
{
   targetNumber = Convert.ToSByte(value, 16);
   if (! isSigned && ((targetNumber & 0x80) != 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 signed byte.", value);
} 
// Displays the following to the console:
//    Unable to convert '0xff' to a signed byte.     
' Create a negative hexadecimal value out of range of the Long type.
Dim sourceNumber As Byte = Byte.MaxValue
Dim isSigned As Boolean = Math.Sign(sourceNumber.MinValue) = -1
Dim value As String = Convert.ToString(sourceNumber, 16)
Dim targetNumber As SByte
Try
   targetNumber = Convert.ToSByte(value, 16)
   If Not isSigned And ((targetNumber And &H80) <> 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 signed byte.", value)
End Try 
' Displays the following to the console:
'    Unable to convert '0xff' to a signed byte.     

ToSByte(String, IFormatProvider)

重要

此 API 不符合 CLS。

使用指定的区域性特定格式设置信息,将数字的指定字符串表示形式转换为等效的 8 位带符号整数。Converts the specified string representation of a number to an equivalent 8-bit signed integer, using the specified culture-specific formatting information.

public:
 static System::SByte ToSByte(System::String ^ value, IFormatProvider ^ provider);
[System.CLSCompliant(false)]
public static sbyte ToSByte (string value, IFormatProvider provider);
static member ToSByte : string * IFormatProvider -> sbyte
Public Shared Function ToSByte (value As String, provider As IFormatProvider) As SByte

参数

value
String

包含要转换的数字的字符串。A string that contains the number to convert.

provider
IFormatProvider

一个提供区域性特定的格式设置信息的对象。An object that supplies culture-specific formatting information.

返回

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

属性

异常

valuenullvalue is null.

value 不由一个可选符号后跟一系列数字 (0-9) 组成。value does not consist of an optional sign followed by a sequence of digits (0 through 9).

value 表示一个小于 MinValue 或大于 MaxValue 的数字。value represents a number that is less than MinValue or greater than MaxValue.

示例

下面的示例使用 IFormatProvider 对象 ToSByte 方法转换 SByte 值的字符串表示形式。The following example converts string representations of SByte values with the ToSByte method, using an IFormatProvider object.

// Example of the Convert::ToSByte( String* ) and 
// Convert::ToSByte( 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 ConvertToSByte( String^ numericStr, IFormatProvider^ provider )
{
   Object^ defaultValue;
   Object^ providerValue;
   
   // Convert numericStr to SByte without a format provider.
   try
   {
      defaultValue = Convert::ToSByte( numericStr );
   }
   catch ( Exception^ ex ) 
   {
      defaultValue = GetExceptionType( ex );
   }

   
   // Convert numericStr to SByte with a format provider.
   try
   {
      providerValue = Convert::ToSByte( 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->NumberNegativePattern = 0;
   Console::WriteLine( "This example of\n"
   "  Convert::ToSByte( String* ) and \n"
   "  Convert::ToSByte( String*, IFormatProvider* ) "
   "\ngenerates the following output. It converts "
   "several strings to \nSByte 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.
   ConvertToSByte( "123", provider );
   ConvertToSByte( "+123", provider );
   ConvertToSByte( "pos 123", provider );
   ConvertToSByte( "-123", provider );
   ConvertToSByte( "neg 123", provider );
   ConvertToSByte( "123.", provider );
   ConvertToSByte( "(123)", provider );
   ConvertToSByte( "128", provider );
   ConvertToSByte( "-129", provider );
}

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

String to convert   Default/exception   Provider/exception
-----------------   -----------------   ------------------
123                 123                 123
+123                123                 FormatException
pos 123             FormatException     123
-123                -123                FormatException
neg 123             FormatException     -123
123.                FormatException     FormatException
(123)               FormatException     FormatException
128                 OverflowException   OverflowException
-129                OverflowException   FormatException
*/
// Example of the Convert.ToSByte( string ) and 
// Convert.ToSByte( string, IFormatProvider ) methods.
using System;
using System.Globalization;

class ToSByteProviderDemo
{
    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 ConvertToSByte( string numericStr, 
        IFormatProvider provider )
    {
        object defaultValue;
        object providerValue;

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

        // Convert numericStr to SByte with a format provider.
        try
        {
            providerValue = Convert.ToSByte( 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.NumberNegativePattern = 0;

        Console.WriteLine("This example of\n" +
            "  Convert.ToSByte( string ) and \n" +
            "  Convert.ToSByte( string, IFormatProvider ) " +
            "\ngenerates the following output. It converts " +
            "several strings to \nSByte 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.
        ConvertToSByte( "123", provider );
        ConvertToSByte( "+123", provider );
        ConvertToSByte( "pos 123", provider );
        ConvertToSByte( "-123", provider );
        ConvertToSByte( "neg 123", provider );
        ConvertToSByte( "123.", provider );
        ConvertToSByte( "(123)", provider );
        ConvertToSByte( "128", provider );
        ConvertToSByte( "-129", provider );
    }
}

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

String to convert   Default/exception   Provider/exception
-----------------   -----------------   ------------------
123                 123                 123
+123                123                 FormatException
pos 123             FormatException     123
-123                -123                FormatException
neg 123             FormatException     -123
123.                FormatException     FormatException
(123)               FormatException     FormatException
128                 OverflowException   OverflowException
-129                OverflowException   FormatException
*/ 
' Example of the Convert.ToSByte( String ) and 
' Convert.ToSByte( String, IFormatProvider ) methods.
Imports System.Globalization

Module ToSByteProviderDemo

    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 ConvertToSByte( numericStr As String, _
        provider As IFormatProvider )

        Dim defaultValue    As Object
        Dim providerValue   As Object

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

        ' Convert numericStr to SByte with a format provider.
        Try
            providerValue = Convert.ToSByte( 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.NumberNegativePattern = 0

        Console.WriteLine( "This example of" & vbCrLf & _
            "  Convert.ToSByte( String ) and " & vbCrLf & _
            "  Convert.ToSByte( String, IFormatProvider ) " & _
            vbCrLf & "generates the following output. It " & _
            "converts several strings to " & vbCrLf & "SByte " & _
            "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.
        ConvertToSByte( "123", provider )
        ConvertToSByte( "+123", provider )
        ConvertToSByte( "pos 123", provider )
        ConvertToSByte( "-123", provider )
        ConvertToSByte( "neg 123", provider )
        ConvertToSByte( "123.", provider )
        ConvertToSByte( "(123)", provider )
        ConvertToSByte( "128", provider )
        ConvertToSByte( "-129", provider )
    End Sub 
End Module 

' This example of
'   Convert.ToSByte( String ) and
'   Convert.ToSByte( String, IFormatProvider )
' generates the following output. It converts several strings to
' SByte values, using default formatting or a NumberFormatInfo object.
' 
' String to convert   Default/exception   Provider/exception
' -----------------   -----------------   ------------------
' 123                 123                 123
' +123                123                 FormatException
' pos 123             FormatException     123
' -123                -123                FormatException
' neg 123             FormatException     -123
' 123.                FormatException     FormatException
' (123)               FormatException     FormatException
' 128                 OverflowException   OverflowException
' -129                OverflowException   FormatException

注解

provider 是获取 NumberFormatInfo 对象的 IFormatProvider 实例。provider is an IFormatProvider instance that obtains a NumberFormatInfo object. NumberFormatInfo 对象提供有关 value格式的区域性特定信息。The NumberFormatInfo object provides culture-specific information about the format of value. 如果 null``provider,则使用当前区域性的 NumberFormatInfoIf 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 SByte.TryParse 方法。If you prefer not to handle an exception if the conversion fails, you can call the SByte.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

ToSByte(Object, IFormatProvider)

重要

此 API 不符合 CLS。

使用指定的区域性特定格式信息,将指定对象的值转换为 8 位带符号整数。Converts the value of the specified object to an 8-bit signed integer, using the specified culture-specific formatting information.

public:
 static System::SByte ToSByte(System::Object ^ value, IFormatProvider ^ provider);
[System.CLSCompliant(false)]
public static sbyte ToSByte (object value, IFormatProvider provider);
static member ToSByte : obj * IFormatProvider -> sbyte
Public Shared Function ToSByte (value As Object, provider As IFormatProvider) As SByte

参数

value
Object

一个实现 IConvertible 接口的对象。An object that implements the IConvertible interface.

provider
IFormatProvider

一个提供区域性特定的格式设置信息的对象。An object that supplies culture-specific formatting information.

返回

一个与 value 等效的 8 位带符号整数,如果 valuenull,则为零。An 8-bit signed integer that is equivalent to value, or zero if value is null.

属性

异常

value 的格式不正确。value is not in an appropriate format.

value 不实现 IConvertible 接口。value does not implement the IConvertible interface.

- 或 --or- 不支持转换。The conversion is not supported.

value 表示一个小于 MinValue 或大于 MaxValue 的数字。value represents a number that is less than MinValue or greater than MaxValue.

示例

下面的示例定义了一个 ByteString 类,该类将有符号和无符号字节存储为十六进制字符串以及指示字节符号的字段。The following example defines a ByteString class that stores both signed and unsigned bytes as hexadecimal strings along with a field that indicates the sign of the byte. ByteString 类实现 IConvertible 接口。The ByteString class implements the IConvertible interface. 它的 IConvertible.ToSByte 方法调用 Parse(String, IFormatProvider) 方法来执行转换。Its IConvertible.ToSByte method calls the Parse(String, IFormatProvider) method to perform the conversion. 如果失败,则会引发 OverflowExceptionIf it fails, it throws an OverflowException.

using System;
using System.Globalization;

public enum SignBit { Negative=-1, Zero=0, Positive=1 };

public struct ByteString : IConvertible
{
   private SignBit signBit;
   private string byteString;
   
   public SignBit Sign
   { 
      set { signBit = value; }
      get { return signBit; }
   }

   public string Value
   { 
      set {
         if (value.Trim().Length > 2)
            throw new ArgumentException("The string representation of a byte cannot have more than two characters.");
         else
            byteString = value;
      }
      get { return byteString; }
   }
   
   // IConvertible implementations.
   public TypeCode GetTypeCode() {
      return TypeCode.Object;
   }
   
   public bool ToBoolean(IFormatProvider provider)
   {
      if (signBit == SignBit.Zero)
         return false;
      else
         return true;
   } 
   
   public byte ToByte(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative)
         throw new OverflowException(String.Format("{0} is out of range of the Byte type.", Convert.ToSByte(byteString, 16)));
      else
         return Byte.Parse(byteString, NumberStyles.HexNumber);
   }
   
   public char ToChar(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative) { 
         throw new OverflowException(String.Format("{0} is out of range of the Char type.", Convert.ToSByte(byteString, 16)));
      }
      else {
         byte byteValue = Byte.Parse(this.byteString, NumberStyles.HexNumber);
         return Convert.ToChar(byteValue);
      }                
   } 
   
   public DateTime ToDateTime(IFormatProvider provider)
   {
      throw new InvalidCastException("ByteString to DateTime conversion is not supported.");
   }
   
   public decimal ToDecimal(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative) 
      {
         sbyte byteValue = SByte.Parse(byteString, NumberStyles.HexNumber);
         return Convert.ToDecimal(byteValue);
      }
      else 
      {
         byte byteValue = Byte.Parse(byteString, NumberStyles.HexNumber);
         return Convert.ToDecimal(byteValue);
      }
   }
   
   public double ToDouble(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative)
         return Convert.ToDouble(SByte.Parse(byteString, NumberStyles.HexNumber));
      else
         return Convert.ToDouble(Byte.Parse(byteString, NumberStyles.HexNumber));
   }   
   
   public short ToInt16(IFormatProvider provider) 
   {
      if (signBit == SignBit.Negative)
         return Convert.ToInt16(SByte.Parse(byteString, NumberStyles.HexNumber));
      else
         return Convert.ToInt16(Byte.Parse(byteString, NumberStyles.HexNumber));
   }
   
   public int ToInt32(IFormatProvider provider) 
   {
      if (signBit == SignBit.Negative)
         return Convert.ToInt32(SByte.Parse(byteString, NumberStyles.HexNumber));
      else
         return Convert.ToInt32(Byte.Parse(byteString, NumberStyles.HexNumber));
   }
   
   public long ToInt64(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative)
         return Convert.ToInt64(SByte.Parse(byteString, NumberStyles.HexNumber));
      else
         return Convert.ToInt64(Byte.Parse(byteString, NumberStyles.HexNumber));
   }
   
   public sbyte ToSByte(IFormatProvider provider)
   {
      try {
         return SByte.Parse(byteString, NumberStyles.HexNumber);
      }   
      catch (OverflowException e) {
         throw new OverflowException(String.Format("{0} is outside the range of the SByte type.", 
                                                   Byte.Parse(byteString, NumberStyles.HexNumber)), e);
      } 
   }

   public float ToSingle(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative)
         return Convert.ToSingle(SByte.Parse(byteString, NumberStyles.HexNumber));
      else
         return Convert.ToSingle(Byte.Parse(byteString, NumberStyles.HexNumber));
   }

   public string ToString(IFormatProvider provider)
   {
      return "0x" + this.byteString;
   }
   
   public object ToType(Type conversionType, IFormatProvider provider)
   {
      switch (Type.GetTypeCode(conversionType))
      {
         case TypeCode.Boolean: 
            return this.ToBoolean(null);
         case TypeCode.Byte:
            return this.ToByte(null);
         case TypeCode.Char:
            return this.ToChar(null);
         case TypeCode.DateTime:
            return this.ToDateTime(null);
         case TypeCode.Decimal:
            return this.ToDecimal(null);
         case TypeCode.Double:
            return this.ToDouble(null);
         case TypeCode.Int16:
            return this.ToInt16(null);
         case TypeCode.Int32:
            return this.ToInt32(null);
         case TypeCode.Int64:
            return this.ToInt64(null);
         case TypeCode.Object:
            if (typeof(ByteString).Equals(conversionType))
               return this;
            else
               throw new InvalidCastException(String.Format("Conversion to a {0} is not supported.", conversionType.Name));
         case TypeCode.SByte:
            return this.ToSByte(null);
         case TypeCode.Single:
            return this.ToSingle(null);
         case TypeCode.String:
            return this.ToString(null);
         case TypeCode.UInt16:
            return this.ToUInt16(null);
         case TypeCode.UInt32:
            return this.ToUInt32(null);
         case TypeCode.UInt64:
            return this.ToUInt64(null);   
         default:
            throw new InvalidCastException(String.Format("Conversion to {0} is not supported.", conversionType.Name));   
      }
   }
   
   public UInt16 ToUInt16(IFormatProvider provider) 
   {
      if (signBit == SignBit.Negative)
         throw new OverflowException(String.Format("{0} is outside the range of the UInt16 type.", 
                                                   SByte.Parse(byteString, NumberStyles.HexNumber)));
      else
         return Convert.ToUInt16(Byte.Parse(byteString, NumberStyles.HexNumber));
   }

   public UInt32 ToUInt32(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative)
         throw new OverflowException(String.Format("{0} is outside the range of the UInt32 type.", 
                                                   SByte.Parse(byteString, NumberStyles.HexNumber)));
      else
         return Convert.ToUInt32(Byte.Parse(byteString, NumberStyles.HexNumber));
   }
   
   public UInt64 ToUInt64(IFormatProvider provider) 
   {
      if (signBit == SignBit.Negative)
         throw new OverflowException(String.Format("{0} is outside the range of the UInt64 type.", 
                                                   SByte.Parse(byteString, NumberStyles.HexNumber)));
      else
         return Convert.ToUInt64(Byte.Parse(byteString, NumberStyles.HexNumber));
   }
}
Imports System.Globalization

Public Enum SignBit As Integer
   Positive = 1
   Zero = 0
   Negative = -1
End Enum

Public Structure ByteString : Implements IConvertible
   Private signBit As SignBit
   Private byteString As String
   
   Public Property Sign As SignBit
      Set
         signBit = value
      End Set
      Get
         Return signBit
      End Get
   End Property
   
   Public Property Value As String
      Set
         If value.Trim().Length > 2 Then
            Throw New ArgumentException("The string representation of a byte cannot have more than two characters.")
         Else
            byteString = value
         End If   
      End Set
      Get
         Return byteString
      End Get
   End Property
   
   ' IConvertible implementations.
   Public Function GetTypeCode() As TypeCode _
                   Implements IConvertible.GetTypeCode
      Return TypeCode.Object
   End Function
   
   Public Function ToBoolean(provider As IFormatProvider) As Boolean _
                   Implements IConvertible.ToBoolean
      If signBit = SignBit.Zero Then
         Return False
      Else
         Return True
      End If
   End Function 
   
   Public Function ToByte(provider As IFormatProvider) As Byte _
                   Implements IConvertible.ToByte
      If signBit = signBit.Negative Then
         Throw New OverflowException(String.Format("{0} is out of range of the Byte type.", Convert.ToSByte(byteString, 16))) 
      Else
         Return Byte.Parse(byteString, NumberStyles.HexNumber)
      End If       
   End Function
   
   Public Function ToChar(provider As IFormatProvider) As Char _
                   Implements IConvertible.ToChar
      If signBit = signBit.Negative Then 
         Throw New OverflowException(String.Format("{0} is out of range of the Char type.", Convert.ToSByte(byteString, 16)))
      Else
         Dim byteValue As Byte = Byte.Parse(Me.byteString, NumberStyles.HexNumber)
         Return Convert.ToChar(byteValue)
      End If                
   End Function 
   
   Public Function ToDateTime(provider As IFormatProvider) As Date _
                   Implements IConvertible.ToDateTime
      Throw New InvalidCastException("ByteString to DateTime conversion is not supported.")
   End Function
   
   Public Function ToDecimal(provider As IFormatProvider) As Decimal _
                   Implements IConvertible.ToDecimal
      If signBit = signBit.Negative Then
         Dim byteValue As SByte = SByte.Parse(byteString, NumberStyles.HexNumber)
         Return Convert.ToDecimal(byteValue)
      Else
         Dim byteValue As Byte = Byte.Parse(byteString, NumberStyles.HexNumber)
         Return Convert.ToDecimal(byteValue)
      End If
   End Function
   
   Public Function ToDouble(provider As IFormatProvider) As Double _
                   Implements IConvertible.ToDouble
      If signBit = signBit.Negative Then
         Return Convert.ToDouble(SByte.Parse(byteString, NumberStyles.HexNumber))
      Else
         Return Convert.ToDouble(Byte.Parse(byteString, NumberStyles.HexNumber))
      End If   
   End Function   
   
   Public Function ToInt16(provider As IFormatProvider) As Int16 _
                   Implements IConvertible.ToInt16
      If signBit = signBit.Negative Then
         Return Convert.ToInt16(SByte.Parse(byteString, NumberStyles.HexNumber))
      Else
         Return Convert.ToInt16(Byte.Parse(byteString, NumberStyles.HexNumber))
      End If   
   End Function
   
   Public Function ToInt32(provider As IFormatProvider) As Int32 _
                   Implements IConvertible.ToInt32
      If signBit = signBit.Negative Then
         Return Convert.ToInt32(SByte.Parse(byteString, NumberStyles.HexNumber))
      Else
         Return Convert.ToInt32(Byte.Parse(byteString, NumberStyles.HexNumber))
      End If   
   End Function
   
   Public Function ToInt64(provider As IFormatProvider) As Int64 _
                   Implements IConvertible.ToInt64
      If signBit = signBit.Negative Then
         Return Convert.ToInt64(SByte.Parse(byteString, NumberStyles.HexNumber))
      Else
         Return Convert.ToInt64(Byte.Parse(byteString, NumberStyles.HexNumber))
      End If   
   End Function
   
   Public Function ToSByte(provider As IFormatProvider) As SByte _
                   Implements IConvertible.ToSByte
      Try
         Return SByte.Parse(byteString, NumberStyles.HexNumber)
      Catch e As OverflowException
         Throw New OverflowException(String.Format("{0} is outside the range of the SByte type.", _
                                                   Byte.Parse(byteString, NumberStyles.HexNumber)))
      End Try   
   End Function

   Public Function ToSingle(provider As IFormatProvider) As Single _
                   Implements IConvertible.ToSingle
      If signBit = signBit.Negative Then
         Return Convert.ToSingle(SByte.Parse(byteString, NumberStyles.HexNumber))
      Else
         Return Convert.ToSingle(Byte.Parse(byteString, NumberStyles.HexNumber))
      End If   
   End Function

   Public Overloads Function ToString(provider As IFormatProvider) As String _
                   Implements IConvertible.ToString
      Return Me.byteString
   End Function
   
   Public Function ToType(conversionType As Type, provider As IFormatProvider) As Object _
                   Implements IConvertible.ToType
      Select Case Type.GetTypeCode(conversionType)
         Case TypeCode.Boolean 
            Return Me.ToBoolean(Nothing)
         Case TypeCode.Byte
            Return Me.ToByte(Nothing)
         Case TypeCode.Char
            Return Me.ToChar(Nothing)
         Case TypeCode.DateTime
            Return Me.ToDateTime(Nothing)
         Case TypeCode.Decimal
            Return Me.ToDecimal(Nothing)
         Case TypeCode.Double
            Return Me.ToDouble(Nothing)
         Case TypeCode.Int16
            Return Me.ToInt16(Nothing)
         Case TypeCode.Int32
            Return Me.ToInt32(Nothing)
         Case TypeCode.Int64
            Return Me.ToInt64(Nothing)
         Case TypeCode.Object
            If GetType(ByteString).Equals(conversionType) Then
               Return Me
            Else
               Throw New InvalidCastException(String.Format("Conversion to a {0} is not supported.", conversionType.Name))
            End If 
         Case TypeCode.SByte
            Return Me.ToSByte(Nothing)
         Case TypeCode.Single
            Return Me.ToSingle(Nothing)
         Case TypeCode.String
            Return Me.ToString(Nothing)
         Case TypeCode.UInt16
            Return Me.ToUInt16(Nothing)
         Case TypeCode.UInt32
            Return Me.ToUInt32(Nothing)
         Case TypeCode.UInt64
            Return Me.ToUInt64(Nothing)   
         Case Else
            Throw New InvalidCastException(String.Format("Conversion to {0} is not supported.", conversionType.Name))   
            
      End Select
   End Function
   
   Public Function ToUInt16(provider As IFormatProvider) As UInt16 _
                   Implements IConvertible.ToUInt16
      If signBit = signBit.Negative Then
         Throw New OverflowException(String.Format("{0} is outside the range of the UInt16 type.", _
                                                   SByte.Parse(byteString, NumberStyles.HexNumber)))
      Else
         Return Convert.ToUInt16(Byte.Parse(byteString, NumberStyles.HexNumber))
      End If   
   End Function

   Public Function ToUInt32(provider As IFormatProvider) As UInt32 _
                   Implements IConvertible.ToUInt32
      If signBit = signBit.Negative Then
         Throw New OverflowException(String.Format("{0} is outside the range of the UInt32 type.", _
                                                   SByte.Parse(byteString, NumberStyles.HexNumber)))
      Else
         Return Convert.ToUInt32(Byte.Parse(byteString, NumberStyles.HexNumber))
      End If   
   End Function
   
   Public Function ToUInt64(provider As IFormatProvider) As UInt64 _
                   Implements IConvertible.ToUInt64
      If signBit = signBit.Negative Then
         Throw New OverflowException(String.Format("{0} is outside the range of the UInt64 type.", _
                                                   SByte.Parse(byteString, NumberStyles.HexNumber)))
      Else
         Return Convert.ToUInt64(Byte.Parse(byteString, NumberStyles.HexNumber))
      End If   
   End Function
   
End Structure

下面的示例演示如何通过 Convert.ToSByte(Object, IFormatProvider) 方法调用 ByteString 类的 IConvertible.ToSByte 实现。The following example shows how the IConvertible.ToSByte implementation of the ByteString class is called by the Convert.ToSByte(Object, IFormatProvider) method.

public class Class1
{
   public static void Main()
   {
      sbyte positiveByte = 120;
      sbyte negativeByte = -101;

      ByteString positiveString = new ByteString();
      positiveString.Sign = (SignBit) Math.Sign(positiveByte);
      positiveString.Value = positiveByte.ToString("X2");
      
      ByteString negativeString = new ByteString();
      negativeString.Sign = (SignBit) Math.Sign(negativeByte);
      negativeString.Value = negativeByte.ToString("X2");
      
      try {
         Console.WriteLine("'{0}' converts to {1}.", positiveString.Value, Convert.ToSByte(positiveString));
      }
      catch (OverflowException) {
         Console.WriteLine("0x{0} is outside the range of the Byte type.", positiveString.Value);
      }

      try {
         Console.WriteLine("'{0}' converts to {1}.", negativeString.Value, Convert.ToSByte(negativeString));
      }
      catch (OverflowException) {
         Console.WriteLine("0x{0} is outside the range of the Byte type.", negativeString.Value);
      }   
   }
}
// The example displays the following output:
//       '78' converts to 120.
//       '9B' converts to -101.
Module modMain
   Public Sub Main()
      Dim positiveByte As SByte = 120
      Dim negativeByte As SByte = -101
      
      
      Dim positiveString As New ByteString()
      positiveString.Sign = CType(Math.Sign(positiveByte), SignBit)
      positiveString.Value = positiveByte.ToString("X2")
      
      Dim negativeString As New ByteString()
      negativeString.Sign = CType(Math.Sign(negativeByte), SignBit)
      negativeString.Value = negativeByte.ToString("X2")
      
      Try
         Console.WriteLine("'{0}' converts to {1}.", positiveString.Value, Convert.ToSByte(positiveString))
      Catch e As OverflowException
         Console.WriteLine("0x{0} is outside the range of the Byte type.", positiveString.Value)
      End Try

      Try
         Console.WriteLine("'{0}' converts to {1}.", negativeString.Value, Convert.ToSByte(negativeString))
      Catch e As OverflowException
         Console.WriteLine("0x{0} is outside the range of the Byte type.", negativeString.Value)
      End Try   
   End Sub
End Module
' The example dosplays the following output:
'       '78' converts to 120.
'       '9B' converts to -101.

注解

provider 使用户能够指定与 value内容有关的区域性特定的转换信息。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 String,则 provider 可能会提供有关用于表示该数字的表示法的特定于区域性的信息。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.

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

ToSByte(UInt64)

重要

此 API 不符合 CLS。

将指定的 64 位无符号整数的值转换为等效的 8 位有符号整数。Converts the value of the specified 64-bit unsigned integer to an equivalent 8-bit signed integer.

public:
 static System::SByte ToSByte(System::UInt64 value);
[System.CLSCompliant(false)]
public static sbyte ToSByte (ulong value);
static member ToSByte : uint64 -> sbyte
Public Shared Function ToSByte (value As ULong) As SByte

参数

value
UInt64

要转换的 64 位无符号整数。The 64-bit unsigned integer to convert.

返回

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

属性

异常

value 大于 MaxValue 或小于 MinValuevalue is greater than MaxValue or less than MinValue.

示例

下面的示例尝试将长整数数组中的每个元素转换为有符号字节。The following example attempts to convert each element in an array of long integers to a signed byte.

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

foreach (ulong number in numbers)
{
   try {
      result = Convert.ToSByte(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 SByte type.",
                        number.GetType().Name, number);
   }
}
// The example displays the following output:
//    Converted the UInt64 value 0 to the SByte value 0.
//    Converted the UInt64 value 121 to the SByte value 121.
//    The UInt64 value 340 is outside the range of the SByte type.
//    The UInt64 value 18446744073709551615 is outside the range of the SByte type.
Dim numbers() As ULong = { UInt64.MinValue, 121, 340, UInt64.MaxValue }
Dim result As SByte
For Each number As ULong In numbers
   Try
      result = Convert.ToSByte(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 SByte type.", _
                        number.GetType().Name, number)
   End Try
Next
' The example displays the following output:
'    Converted the UInt64 value 0 to the SByte value 0.
'    Converted the UInt64 value 121 to the SByte value 121.
'    The UInt64 value 340 is outside the range of the SByte type.
'    The UInt64 value 18446744073709551615 is outside the range of the SByte type.

ToSByte(UInt32)

重要

此 API 不符合 CLS。

将指定的 32 位无符号整数的值转换为等效的 8 位有符号整数。Converts the value of the specified 32-bit unsigned integer to an equivalent 8-bit signed integer.

public:
 static System::SByte ToSByte(System::UInt32 value);
[System.CLSCompliant(false)]
public static sbyte ToSByte (uint value);
static member ToSByte : uint32 -> sbyte
Public Shared Function ToSByte (value As UInteger) As SByte

参数

value
UInt32

要转换的 32 位无符号整数。The 32-bit unsigned integer to convert.

返回

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

属性

异常

value 大于 MaxValue 或小于 MinValuevalue is greater than MaxValue or less than MinValue.

示例

下面的示例尝试将整数数组中的每个元素转换为有符号字节。The following example attempts to convert each element in an integer array to a signed byte.

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

foreach (uint number in numbers)
{
   try {
      result = Convert.ToSByte(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 SByte type.",
                        number.GetType().Name, number);
   }
}
// The example displays the following output:
//    Converted the UInt32 value 0 to the SByte value 0.
//    Converted the UInt32 value 121 to the SByte value 121.
//    The UInt32 value 340 is outside the range of the SByte type.
//    The UInt32 value 4294967295 is outside the range of the SByte type.
Dim numbers() As UInteger = { UInt32.MinValue, 121, 340, UInt32.MaxValue }
Dim result As SByte
For Each number As UInteger In numbers
   Try
      result = Convert.ToSByte(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 SByte type.", _
                        number.GetType().Name, number)
   End Try
Next
' The example displays the following output:
'    Converted the UInt32 value 0 to the SByte value 0.
'    Converted the UInt32 value 121 to the SByte value 121.
'    The UInt32 value 340 is outside the range of the SByte type.
'    The UInt32 value 4294967295 is outside the range of the SByte type.

ToSByte(String)

重要

此 API 不符合 CLS。

将数字的指定字符串表示形式转换为等效的 8 位带符号整数。Converts the specified string representation of a number to an equivalent 8-bit signed integer.

public:
 static System::SByte ToSByte(System::String ^ value);
[System.CLSCompliant(false)]
public static sbyte ToSByte (string value);
static member ToSByte : string -> sbyte
Public Shared Function ToSByte (value As String) As SByte

参数

value
String

包含要转换的数字的字符串。A string that contains the number to convert.

返回

value 中数字等效的 8 位带符号整数,如果值为 null,则为 0(零)。An 8-bit signed integer that is equivalent to the number in value, or 0 (zero) if value is null.

属性

异常

value 不由一个可选符号后跟一系列数字 (0-9) 组成。value does not consist of an optional sign followed by a sequence of digits (0 through 9).

value 表示一个小于 MinValue 或大于 MaxValue 的数字。value represents a number that is less than MinValue or greater than MaxValue.

示例

下面的示例使用默认格式设置将 SByte 值的字符串表示形式与 ToSByte 方法一起转换。The following example converts string representations of SByte values with the ToSByte method, using default formatting.

// Example of the Convert::ToSByte( String* ) and 
// Convert::ToSByte( 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 ConvertToSByte( String^ numericStr, IFormatProvider^ provider )
{
   Object^ defaultValue;
   Object^ providerValue;
   
   // Convert numericStr to SByte without a format provider.
   try
   {
      defaultValue = Convert::ToSByte( numericStr );
   }
   catch ( Exception^ ex ) 
   {
      defaultValue = GetExceptionType( ex );
   }

   
   // Convert numericStr to SByte with a format provider.
   try
   {
      providerValue = Convert::ToSByte( 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->NumberNegativePattern = 0;
   Console::WriteLine( "This example of\n"
   "  Convert::ToSByte( String* ) and \n"
   "  Convert::ToSByte( String*, IFormatProvider* ) "
   "\ngenerates the following output. It converts "
   "several strings to \nSByte 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.
   ConvertToSByte( "123", provider );
   ConvertToSByte( "+123", provider );
   ConvertToSByte( "pos 123", provider );
   ConvertToSByte( "-123", provider );
   ConvertToSByte( "neg 123", provider );
   ConvertToSByte( "123.", provider );
   ConvertToSByte( "(123)", provider );
   ConvertToSByte( "128", provider );
   ConvertToSByte( "-129", provider );
}

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

String to convert   Default/exception   Provider/exception
-----------------   -----------------   ------------------
123                 123                 123
+123                123                 FormatException
pos 123             FormatException     123
-123                -123                FormatException
neg 123             FormatException     -123
123.                FormatException     FormatException
(123)               FormatException     FormatException
128                 OverflowException   OverflowException
-129                OverflowException   FormatException
*/
// Example of the Convert.ToSByte( string ) and 
// Convert.ToSByte( string, IFormatProvider ) methods.
using System;
using System.Globalization;

class ToSByteProviderDemo
{
    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 ConvertToSByte( string numericStr, 
        IFormatProvider provider )
    {
        object defaultValue;
        object providerValue;

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

        // Convert numericStr to SByte with a format provider.
        try
        {
            providerValue = Convert.ToSByte( 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.NumberNegativePattern = 0;

        Console.WriteLine("This example of\n" +
            "  Convert.ToSByte( string ) and \n" +
            "  Convert.ToSByte( string, IFormatProvider ) " +
            "\ngenerates the following output. It converts " +
            "several strings to \nSByte 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.
        ConvertToSByte( "123", provider );
        ConvertToSByte( "+123", provider );
        ConvertToSByte( "pos 123", provider );
        ConvertToSByte( "-123", provider );
        ConvertToSByte( "neg 123", provider );
        ConvertToSByte( "123.", provider );
        ConvertToSByte( "(123)", provider );
        ConvertToSByte( "128", provider );
        ConvertToSByte( "-129", provider );
    }
}

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

String to convert   Default/exception   Provider/exception
-----------------   -----------------   ------------------
123                 123                 123
+123                123                 FormatException
pos 123             FormatException     123
-123                -123                FormatException
neg 123             FormatException     -123
123.                FormatException     FormatException
(123)               FormatException     FormatException
128                 OverflowException   OverflowException
-129                OverflowException   FormatException
*/ 
' Example of the Convert.ToSByte( String ) and 
' Convert.ToSByte( String, IFormatProvider ) methods.
Imports System.Globalization

Module ToSByteProviderDemo

    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 ConvertToSByte( numericStr As String, _
        provider As IFormatProvider )

        Dim defaultValue    As Object
        Dim providerValue   As Object

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

        ' Convert numericStr to SByte with a format provider.
        Try
            providerValue = Convert.ToSByte( 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.NumberNegativePattern = 0

        Console.WriteLine( "This example of" & vbCrLf & _
            "  Convert.ToSByte( String ) and " & vbCrLf & _
            "  Convert.ToSByte( String, IFormatProvider ) " & _
            vbCrLf & "generates the following output. It " & _
            "converts several strings to " & vbCrLf & "SByte " & _
            "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.
        ConvertToSByte( "123", provider )
        ConvertToSByte( "+123", provider )
        ConvertToSByte( "pos 123", provider )
        ConvertToSByte( "-123", provider )
        ConvertToSByte( "neg 123", provider )
        ConvertToSByte( "123.", provider )
        ConvertToSByte( "(123)", provider )
        ConvertToSByte( "128", provider )
        ConvertToSByte( "-129", provider )
    End Sub 
End Module 

' This example of
'   Convert.ToSByte( String ) and
'   Convert.ToSByte( String, IFormatProvider )
' generates the following output. It converts several strings to
' SByte values, using default formatting or a NumberFormatInfo object.
' 
' String to convert   Default/exception   Provider/exception
' -----------------   -----------------   ------------------
' 123                 123                 123
' +123                123                 FormatException
' pos 123             FormatException     123
' -123                -123                FormatException
' neg 123             FormatException     -123
' 123.                FormatException     FormatException
' (123)               FormatException     FormatException
' 128                 OverflowException   OverflowException
' -129                OverflowException   FormatException

注解

使用 ToSByte(String) 方法等效于将 value 传递到 SByte.Parse(String) 方法。Using the ToSByte(String) method is equivalent to passing value to the SByte.Parse(String) method. 使用当前线程区域性的格式设置约定解释 valuevalue 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 SByte.TryParse 方法。If you prefer not to handle an exception if the conversion fails, you can call the SByte.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

ToSByte(Single)

重要

此 API 不符合 CLS。

将指定的单精度浮点数的值转换为等效的 8 位带符号整数。Converts the value of the specified single-precision floating-point number to an equivalent 8-bit signed integer.

public:
 static System::SByte ToSByte(float value);
[System.CLSCompliant(false)]
public static sbyte ToSByte (float value);
static member ToSByte : single -> sbyte
Public Shared Function ToSByte (value As Single) As SByte

参数

value
Single

要转换的单精度浮点数。The single-precision floating-point number to convert.

返回

value,舍入为最接近的 8 位有符号整数。value, rounded to the nearest 8-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.

属性

异常

value 大于 MaxValue 或小于 MinValuevalue is greater than MaxValue or less than MinValue.

示例

下面的示例尝试将 Single 值数组中的每个元素转换为有符号字节。The following example attempts to convert each element in an array of Single values to a signed byte.

object[] values = { true, -12, 163, 935, 'x', "104", "103.0", "-1",
                    "1.00e2", "One", 1.00e2};
sbyte result;

foreach (object value in values)
{
   try {
      result = Convert.ToSByte(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 SByte 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 a Byte exists for the {0} value {1}.",
                        value.GetType().Name, value);
                        
   }
}                           
// The example displays the following output:
//    Converted the Boolean value true to the SByte value 1.
//    Converted the Int32 value -12 to the SByte value -12.
//    The Int32 value 163 is outside the range of the SByte type.
//    The Int32 value 935 is outside the range of the SByte type.
//    Converted the Char value x to the SByte value 120.
//    Converted the String value 104 to the SByte value 104.
//    The String value 103.0 is not in a recognizable format.
//    Converted the String value -1 to the SByte 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 SByte value 100.
Dim values() As Object = { True, -12, 163, 935, "x"c, "104", "103.0", "-1", _
                           "1.00e2", "One", 1.00e2}
Dim result As SByte
For Each value As Object In values
   Try
      result = Convert.ToSByte(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 SByte 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 a Byte 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 SByte value 1.
'    Converted the Int32 value -12 to the SByte value -12.
'    The Int32 value 163 is outside the range of the SByte type.
'    The Int32 value 935 is outside the range of the SByte type.
'    Converted the Char value x to the SByte value 120.
'    Converted the String value 104 to the SByte value 104.
'    The String value 103.0 is not in a recognizable format.
'    Converted the String value -1 to the SByte 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 SByte value 100.

另请参阅

ToSByte(Object)

重要

此 API 不符合 CLS。

将指定对象的值转换为 8 位带符号整数。Converts the value of the specified object to an 8-bit signed integer.

public:
 static System::SByte ToSByte(System::Object ^ value);
[System.CLSCompliant(false)]
public static sbyte ToSByte (object value);
static member ToSByte : obj -> sbyte
Public Shared Function ToSByte (value As Object) As SByte

参数

value
Object

用于实现 IConvertible 接口的对象,或为 nullAn object that implements the IConvertible interface, or null.

返回

一个与 value 等效的 8 位带符号整数,如果 valuenull,则为零。An 8-bit signed integer that is equivalent to value, or zero if value is null.

属性

异常

value 的格式不正确。value is not in an appropriate format.

value 不实现 IConvertible 接口。value does not implement the IConvertible interface.

- 或 --or- 不支持转换。The conversion is not supported.

value 表示一个小于 MinValue 或大于 MaxValue 的数字。value represents a number that is less than MinValue or greater than MaxValue.

示例

下面的示例尝试将对象数组中的每个元素转换为有符号字节。The following example attempts to convert each element in an object array to a signed byte.

object[] values = { true, -12, 163, 935, 'x', "104", "103.0", "-1",
                    "1.00e2", "One", 1.00e2};
sbyte result;

foreach (object value in values)
{
   try {
      result = Convert.ToSByte(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 SByte 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 a Byte exists for the {0} value {1}.",
                        value.GetType().Name, value);
                        
   }
}                           
// The example displays the following output:
//    Converted the Boolean value true to the SByte value 1.
//    Converted the Int32 value -12 to the SByte value -12.
//    The Int32 value 163 is outside the range of the SByte type.
//    The Int32 value 935 is outside the range of the SByte type.
//    Converted the Char value x to the SByte value 120.
//    Converted the String value 104 to the SByte value 104.
//    The String value 103.0 is not in a recognizable format.
//    Converted the String value -1 to the SByte 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 SByte value 100.
Dim values() As Object = { True, -12, 163, 935, "x"c, "104", "103.0", "-1", _
                           "1.00e2", "One", 1.00e2}
Dim result As SByte
For Each value As Object In values
   Try
      result = Convert.ToSByte(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 SByte 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 a Byte 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 SByte value 1.
'    Converted the Int32 value -12 to the SByte value -12.
'    The Int32 value 163 is outside the range of the SByte type.
'    The Int32 value 935 is outside the range of the SByte type.
'    Converted the Char value x to the SByte value 120.
'    Converted the String value 104 to the SByte value 104.
'    The String value 103.0 is not in a recognizable format.
'    Converted the String value -1 to the SByte 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 SByte value 100.

注解

返回值是调用的基础类型 valueIConvertible.ToSByte 方法的结果。The return value is the result of invoking the IConvertible.ToSByte method of the underlying type of value.

ToSByte(UInt16)

重要

此 API 不符合 CLS。

将指定的 16 位无符号整数的值转换为等效的 8 位有符号整数。Converts the value of the specified 16-bit unsigned integer to the equivalent 8-bit signed integer.

public:
 static System::SByte ToSByte(System::UInt16 value);
[System.CLSCompliant(false)]
public static sbyte ToSByte (ushort value);
static member ToSByte : uint16 -> sbyte
Public Shared Function ToSByte (value As UShort) As SByte

参数

value
UInt16

要转换的 16 位无符号整数。The 16-bit unsigned integer to convert.

返回

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

属性

异常

value 大于 MaxValuevalue is greater than MaxValue.

示例

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

ushort[] numbers = { UInt16.MinValue, 121, 340, UInt16.MaxValue };
sbyte result;

foreach (ushort number in numbers)
{
   try {
      result = Convert.ToSByte(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 SByte type.",
                        number.GetType().Name, number);
   }
}
// The example displays the following output:
//    Converted the UInt16 value 0 to the SByte value 0.
//    Converted the UInt16 value 121 to the SByte value 121.
//    The UInt16 value 340 is outside the range of the SByte type.
//    The UInt16 value 65535 is outside the range of the SByte type.
Dim numbers() As UShort = { UInt16.MinValue, 121, 340, UInt16.MaxValue }
Dim result As SByte
For Each number As UShort In numbers
   Try
      result = Convert.ToSByte(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 SByte type.", _
                        number.GetType().Name, number)
   End Try
Next
' The example displays the following output:
'    Converted the UInt16 value 0 to the SByte value 0.
'    Converted the UInt16 value 121 to the SByte value 121.
'    The UInt16 value 340 is outside the range of the SByte type.
'    The UInt16 value 65535 is outside the range of the SByte type.

ToSByte(Int32)

重要

此 API 不符合 CLS。

将指定的 32 位有符号整数的值转换为等效的 8 位有符号整数。Converts the value of the specified 32-bit signed integer to an equivalent 8-bit signed integer.

public:
 static System::SByte ToSByte(int value);
[System.CLSCompliant(false)]
public static sbyte ToSByte (int value);
static member ToSByte : int -> sbyte
Public Shared Function ToSByte (value As Integer) As SByte

参数

value
Int32

要转换的 32 位带符号整数。The 32-bit signed integer to convert.

返回

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

属性

异常

value 大于 MaxValue 或小于 MinValuevalue is greater than MaxValue or less than MinValue.

示例

下面的示例尝试将有符号整数数组中的每个元素转换为有符号字节。The following example attempts to convert each element in an array of signed integers to a signed byte.

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

foreach (int number in numbers)
{
   try {
      result = Convert.ToSByte(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 SByte type.",
                        number.GetType().Name, number);
   }
}
// The example displays the following output:
//    The Int32 value -2147483648 is outside the range of the SByte type.
//    Converted the Int32 value -1 to the SByte value -1.
//    Converted the Int32 value 0 to the SByte value 0.
//    Converted the Int32 value 121 to the SByte value 121.
//    The Int32 value 340 is outside the range of the SByte type.
//    The Int32 value 2147483647 is outside the range of the SByte type.
Dim numbers() As Integer = { Int32.MinValue, -1, 0, 121, 340, Int32.MaxValue }
Dim result As SByte
For Each number As Integer In numbers
   Try
      result = Convert.ToSByte(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 SByte type.", _
                        number.GetType().Name, number)
   End Try
Next
' The example displays the following output:
'    The Int32 value -2147483648 is outside the range of the SByte type.
'    Converted the Int32 value -1 to the SByte value -1.
'    Converted the Int32 value 0 to the SByte value 0.
'    Converted the Int32 value 121 to the SByte value 121.
'    The Int32 value 340 is outside the range of the SByte type.
'    The Int32 value 2147483647 is outside the range of the SByte type.

ToSByte(Int64)

重要

此 API 不符合 CLS。

将指定的 64 位有符号整数的值转换为等效的 8 位有符号整数。Converts the value of the specified 64-bit signed integer to an equivalent 8-bit signed integer.

public:
 static System::SByte ToSByte(long value);
[System.CLSCompliant(false)]
public static sbyte ToSByte (long value);
static member ToSByte : int64 -> sbyte
Public Shared Function ToSByte (value As Long) As SByte

参数

value
Int64

要转换的 64 位带符号整数。The 64-bit signed integer to convert.

返回

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

属性

异常

value 大于 MaxValue 或小于 MinValuevalue is greater than MaxValue or less than MinValue.

示例

下面的示例尝试将长整数数组中的每个元素转换为有符号字节。The following example attempts to convert each element in an array of long integers to a signed byte.

long[] numbers = { Int64.MinValue, -1, 0, 121, 340, Int64.MaxValue };
sbyte result;
foreach (long number in numbers)
{
   try {
      result = Convert.ToSByte(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 SByte type.",
                        number.GetType().Name, number);
   }
}
// The example displays the following output:
//    The Int64 value -9223372036854775808 is outside the range of the SByte type.
//    Converted the Int64 value -1 to the SByte value -1.
//    Converted the Int64 value 0 to the SByte value 0.
//    Converted the Int64 value 121 to the SByte value 121.
//    The Int64 value 340 is outside the range of the SByte type.
//    The Int64 value 9223372036854775807 is outside the range of the SByte type.
Dim numbers() As Long = { Int64.MinValue, -1, 0, 121, 340, Int64.MaxValue }
Dim result As SByte
For Each number As Long In numbers
   Try
      result = Convert.ToSByte(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 SByte type.", _
                        number.GetType().Name, number)
   End Try
Next
' The example displays the following output:
'    The Int64 value -9223372036854775808 is outside the range of the SByte type.
'    Converted the Int64 value -1 to the SByte value -1.
'    Converted the Int64 value 0 to the SByte value 0.
'    Converted the Int64 value 121 to the SByte value 121.
'    The Int64 value 340 is outside the range of the SByte type.
'    The Int64 value 9223372036854775807 is outside the range of the SByte type.

ToSByte(Byte)

重要

此 API 不符合 CLS。

将指定的 8 位无符号整数的值转换为等效的 8 位有符号整数。Converts the value of the specified 8-bit unsigned integer to the equivalent 8-bit signed integer.

public:
 static System::SByte ToSByte(System::Byte value);
[System.CLSCompliant(false)]
public static sbyte ToSByte (byte value);
static member ToSByte : byte -> sbyte
Public Shared Function ToSByte (value As Byte) As SByte

参数

value
Byte

要转换的 8 位无符号整数。The 8-bit unsigned integer to convert.

返回

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

属性

异常

value 大于 MaxValuevalue is greater than MaxValue.

示例

下面的示例尝试将字节数组中的每个元素转换为有符号字节。The following example attempts to convert each element in a byte array to a signed byte.

byte[] numbers = { Byte.MinValue, 10, 100, Byte.MaxValue };
sbyte result;

foreach (byte number in numbers)
{
   try {
      result = Convert.ToSByte(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 SByte type.",
                        number.GetType().Name, number);
   }
}
// The example displays the following output:
//    Converted the Byte value 0 to the SByte value 0.
//    Converted the Byte value 10 to the SByte value 10.
//    Converted the Byte value 100 to the SByte value 100.
//    The Byte value 255 is outside the range of the SByte type.
Dim numbers() As Byte = { Byte.MinValue, 10, 100, Byte.MaxValue }
Dim result As SByte
For Each number As Byte In numbers
   Try
      result = Convert.ToSByte(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 SByte type.", _
                        number.GetType().Name, number)
   End Try
Next
' The example displays the following output:
'    Converted the Byte value 0 to the SByte value 0.
'    Converted the Byte value 10 to the SByte value 10.
'    Converted the Byte value 100 to the SByte value 100.
'    The Byte value 255 is outside the range of the SByte type.

ToSByte(Char)

重要

此 API 不符合 CLS。

将指定的 Unicode 字符的值转换为等效的 8 位有符号整数。Converts the value of the specified Unicode character to the equivalent 8-bit signed integer.

public:
 static System::SByte ToSByte(char value);
[System.CLSCompliant(false)]
public static sbyte ToSByte (char value);
static member ToSByte : char -> sbyte
Public Shared Function ToSByte (value As Char) As SByte

参数

value
Char

要转换的 Unicode 字符。The Unicode character to convert.

返回

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

属性

异常

value 大于 MaxValuevalue is greater than MaxValue.

示例

下面的示例尝试将 Char 值数组中的每个元素转换为有符号字节。The following example attempts to convert each element in an array of Char values to a signed byte.

char[] chars = { 'a', 'z', '\u0007', '\u0200', '\u1023' };
foreach (char ch in chars)
{
   try {
      sbyte result = Convert.ToSByte(ch);
      Console.WriteLine("{0} is converted to {1}.", ch, result);
   }   
   catch (OverflowException) {
      Console.WriteLine("Unable to convert u+{0} to a byte.",
                        Convert.ToInt16(ch).ToString("X4"));
   }
}   
// The example displays the following output:
//    a is converted to 97.
//    z is converted to 122.
//     is converted to 7.
//    Unable to convert u+00C8 to a byte.
//    Unable to convert u+03FF to a byte.
Dim chars() As Char = { "a"c, "z"c, ChrW(7), ChrW(200), ChrW(1023) }
For Each ch As Char in chars
   Try
      Dim result As SByte = Convert.ToSByte(ch)
      Console.WriteLine("{0} is converted to {1}.", ch, result)
   Catch e As OverflowException
      Console.WriteLine("Unable to convert u+{0} to a byte.", _
                        AscW(ch).ToString("X4"))
   End Try
Next   
' The example displays the following output:
'    a is converted to 97.
'    z is converted to 122.
'     is converted to 7.
'    Unable to convert u+00C8 to a byte.
'    Unable to convert u+03FF to a byte.

ToSByte(DateTime)

重要

此 API 不符合 CLS。

调用此方法始终引发 InvalidCastExceptionCalling this method always throws InvalidCastException.

public:
 static System::SByte ToSByte(DateTime value);
[System.CLSCompliant(false)]
public static sbyte ToSByte (DateTime value);
static member ToSByte : DateTime -> sbyte
Public Shared Function ToSByte (value As DateTime) As SByte

参数

value
DateTime

要转换的日期和时间值。The date and time value to convert.

返回

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

属性

异常

不支持此转换。This conversion is not supported.

ToSByte(Boolean)

重要

此 API 不符合 CLS。

将指定的布尔值转换为等效的 8 位带符号整数。Converts the specified Boolean value to the equivalent 8-bit signed integer.

public:
 static System::SByte ToSByte(bool value);
[System.CLSCompliant(false)]
public static sbyte ToSByte (bool value);
static member ToSByte : bool -> sbyte
Public Shared Function ToSByte (value As Boolean) As SByte

参数

value
Boolean

要转换的布尔值。The Boolean value to convert.

返回

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

属性

示例

下面的示例将 truefalse 的布尔值转换为有符号的字节值。The following example converts the Boolean values true and false to signed byte values.

bool falseFlag = false;
bool trueFlag = true;

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

ToSByte(Double)

重要

此 API 不符合 CLS。

将指定的双精度浮点数的值转换为等效的 8 位带符号整数。Converts the value of the specified double-precision floating-point number to an equivalent 8-bit signed integer.

public:
 static System::SByte ToSByte(double value);
[System.CLSCompliant(false)]
public static sbyte ToSByte (double value);
static member ToSByte : double -> sbyte
Public Shared Function ToSByte (value As Double) As SByte

参数

value
Double

要转换的双精度浮点数。The double-precision floating-point number to convert.

返回

value,舍入为最接近的 8 位有符号整数。value, rounded to the nearest 8-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.

属性

异常

value 大于 MaxValue 或小于 MinValuevalue is greater than MaxValue or less than MinValue.

示例

下面的示例尝试将 Double 值数组中的每个元素转换为有符号字节。The following example attempts to convert each element in an array of Double values to a signed byte.

double[] numbers = { Double.MinValue, -129.5, -12.7, 0, 16,
                     103.6, 255.0, 1.63509e17, Double.MaxValue};
sbyte result;

foreach (double number in numbers)
{
   try {
      result = Convert.ToSByte(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 SByte type.",
                        number.GetType().Name, number);
   }
}                                  
// The example displays the following output:
//    The Double value -1.79769313486232E+308 is outside the range of the SByte type.
//    The Double value -129.5 is outside the range of the SByte type.
//    Converted the Double value -12.7 to the SByte value -13.
//    Converted the Double value 0 to the SByte value 0.
//    Converted the Double value 16 to the SByte value 16.
//    Converted the Double value 103.6 to the SByte value 104.
//    The Double value 255 is outside the range of the SByte type.
//    The Double value 1.63509E+17 is outside the range of the SByte type.
//    The Double value 1.79769313486232E+308 is outside the range of the SByte type.
Dim numbers() As Double = { Double.MinValue, -129.5, -12.7, 0, 16, _
                            103.6, 255.0, 1.63509e17, Double.MaxValue}
Dim result As SByte

For Each number As Double In numbers
   Try
      result = Convert.ToSByte(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 SByte type.", _
                        number.GetType().Name, number)
   End Try
Next                                  
' The example displays the following output:
'    The Double value -1.79769313486232E+308 is outside the range of the SByte type.
'    The Double value -129.5 is outside the range of the SByte type.
'    Converted the Double value -12.7 to the SByte value -13.
'    Converted the Double value 0 to the SByte value 0.
'    Converted the Double value 16 to the SByte value 16.
'    Converted the Double value 103.6 to the SByte value 104.
'    The Double value 255 is outside the range of the SByte type.
'    The Double value 1.63509E+17 is outside the range of the SByte type.
'    The Double value 1.79769313486232E+308 is outside the range of the SByte type.

另请参阅

ToSByte(Int16)

重要

此 API 不符合 CLS。

将指定的 16 位带符号整数的值转换为等效的 8 位带符号整数。Converts the value of the specified 16-bit signed integer to the equivalent 8-bit signed integer.

public:
 static System::SByte ToSByte(short value);
[System.CLSCompliant(false)]
public static sbyte ToSByte (short value);
static member ToSByte : int16 -> sbyte
Public Shared Function ToSByte (value As Short) As SByte

参数

value
Int16

要转换的 16 位带符号整数。The 16-bit signed integer to convert.

返回

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

属性

异常

value 大于 MaxValue 或小于 MinValuevalue is greater than MaxValue or less than MinValue.

示例

下面的示例尝试将有符号的16位整数数组中的每个元素转换为有符号字节。The following example attempts to convert each element in an array of signed 16-bit integers to a signed byte.

short[] numbers = { Int16.MinValue, -1, 0, 121, 340, Int16.MaxValue };
sbyte result;
foreach (short number in numbers)
{
   try {
      result = Convert.ToSByte(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 SByte type.",
                        number.GetType().Name, number);
   }
}
// The example displays the following output:
//    The Int16 value -32768 is outside the range of the SByte type.
//    Converted the Int16 value -1 to the SByte value -1.
//    Converted the Int16 value 0 to the SByte value 0.
//    Converted the Int16 value 121 to the SByte value 121.
//    The Int16 value 340 is outside the range of the SByte type.
//    The Int16 value 32767 is outside the range of the SByte type.
Dim numbers() As Short = { Int16.MinValue, -1, 0, 121, 340, Int16.MaxValue }
Dim result As SByte
For Each number As Short In numbers
   Try
      result = Convert.ToSByte(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 SByte type.", _
                        number.GetType().Name, number)
   End Try
Next
' The example displays the following output:
'    The Int16 value -32768 is outside the range of the SByte type.
'    Converted the Int16 value -1 to the SByte value -1.
'    Converted the Int16 value 0 to the SByte value 0.
'    Converted the Int16 value 121 to the SByte value 121.
'    The Int16 value 340 is outside the range of the SByte type.
'    The Int16 value 32767 is outside the range of the SByte type.

ToSByte(Decimal)

重要

此 API 不符合 CLS。

将指定的十进制数的值转换为等效的 8 位带符号整数。Converts the value of the specified decimal number to an equivalent 8-bit signed integer.

public:
 static System::SByte ToSByte(System::Decimal value);
[System.CLSCompliant(false)]
public static sbyte ToSByte (decimal value);
static member ToSByte : decimal -> sbyte
Public Shared Function ToSByte (value As Decimal) As SByte

参数

value
Decimal

要转换的十进制数。The decimal number to convert.

返回

value,舍入为最接近的 8 位有符号整数。value, rounded to the nearest 8-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.

属性

异常

value 大于 MaxValue 或小于 MinValuevalue is greater than MaxValue or less than MinValue.

示例

下面的示例尝试将 Decimal 值数组中的每个元素转换为有符号字节。The following example attempts to convert each element in an array of Decimal values to a signed byte.

decimal[] numbers = { Decimal.MinValue, -129.5m, -12.7m, 0m, 16m,
                      103.6m, 255.0m, Decimal.MaxValue };
sbyte result;

foreach (decimal number in numbers)
{
   try {
      result = Convert.ToSByte(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 SByte type.",
                        number.GetType().Name, number);
   }
}                         
// The example displays the following output:
//    The Decimal value -79228162514264337593543950335 is outside the range of the SByte type.
//    The Decimal value -129.5 is outside the range of the SByte type.
//    Converted the Decimal value -12.7 to the SByte value -13.
//    Converted the Decimal value 0 to the SByte value 0.
//    Converted the Decimal value 16 to the SByte value 16.
//    Converted the Decimal value 103.6 to the SByte value 104.
//    The Decimal value 255 is outside the range of the SByte type.
//    The Decimal value 79228162514264337593543950335 is outside the range of the SByte type.
Dim numbers() As Decimal = { Decimal.MinValue, -129.5d, -12.7d, 0d, 16d, _
                             103.6d, 255.0d, Decimal.MaxValue }
Dim result As SByte

For Each number As Decimal In numbers
   Try
      result = Convert.ToSByte(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 SByte type.", _
                        number.GetType().Name, number)
   End Try
Next                         
' The example displays the following output:
'    The Decimal value -79228162514264337593543950335 is outside the range of the SByte type.
'    The Decimal value -129.5 is outside the range of the SByte type.
'    Converted the Decimal value -12.7 to the SByte value -13.
'    Converted the Decimal value 0 to the SByte value 0.
'    Converted the Decimal value 16 to the SByte value 16.
'    Converted the Decimal value 103.6 to the SByte value 104.
'    The Decimal value 255 is outside the range of the SByte type.
'    The Decimal value 79228162514264337593543950335 is outside the range of the SByte type.

另请参阅

适用于