Convert.ToInt32 方法
定义
将指定的值转换为 32 位有符号整数。Converts a specified value to a 32-bit signed integer.
重载
| ToInt32(String) |
将数字的指定字符串表示形式转换为等效的 32 位带符号整数。Converts the specified string representation of a number to an equivalent 32-bit signed integer. |
| ToInt32(UInt16) |
将指定的 16 位无符号整数的值转换为等效的 32 位有符号整数。Converts the value of the specified 16-bit unsigned integer to the equivalent 32-bit signed integer. |
| ToInt32(UInt32) |
将指定的 32 位无符号整数的值转换为等效的 32 位有符号整数。Converts the value of the specified 32-bit unsigned integer to an equivalent 32-bit signed integer. |
| ToInt32(Single) |
将指定的单精度浮点数的值转换为等效的 32 位带符号整数。Converts the value of the specified single-precision floating-point number to an equivalent 32-bit signed integer. |
| ToInt32(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 32 位带符号整数。Converts the value of the specified object to a 32-bit signed integer, using the specified culture-specific formatting information. |
| ToInt32(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 32 位带符号整数。Converts the specified string representation of a number to an equivalent 32-bit signed integer, using the specified culture-specific formatting information. |
| ToInt32(String, Int32) |
将指定基数的数字的字符串表示形式转换为等效的 32 位有符号整数。Converts the string representation of a number in a specified base to an equivalent 32-bit signed integer. |
| ToInt32(UInt64) |
将指定的 64 位无符号整数的值转换为等效的 32 位有符号整数。Converts the value of the specified 64-bit unsigned integer to an equivalent 32-bit signed integer. |
| ToInt32(Object) |
将指定对象的值转换为 32 位带符号整数。Converts the value of the specified object to a 32-bit signed integer. |
| ToInt32(SByte) |
将指定的 8 位带符号整数的值转换为等效的 32 位带符号整数。Converts the value of the specified 8-bit signed integer to the equivalent 32-bit signed integer. |
| ToInt32(Int64) |
将指定的 64 位有符号整数的值转换为等效的 32 位有符号整数。Converts the value of the specified 64-bit signed integer to an equivalent 32-bit signed integer. |
| ToInt32(Int32) |
返回指定的 32 位有符号整数;不执行实际的转换。Returns the specified 32-bit signed integer; no actual conversion is performed. |
| ToInt32(Int16) |
将指定的 16 位有符号整数的值转换为等效的 32 位有符号整数。Converts the value of the specified 16-bit signed integer to an equivalent 32-bit signed integer. |
| ToInt32(Double) |
将指定的双精度浮点数的值转换为等效的 32 位带符号整数。Converts the value of the specified double-precision floating-point number to an equivalent 32-bit signed integer. |
| ToInt32(Decimal) |
将指定的十进制数的值转换为等效的 32 位带符号整数。Converts the value of the specified decimal number to an equivalent 32-bit signed integer. |
| ToInt32(DateTime) |
调用此方法始终引发 InvalidCastException。Calling this method always throws InvalidCastException. |
| ToInt32(Char) |
将指定的 Unicode 字符的值转换为等效的 32 位有符号整数。Converts the value of the specified Unicode character to the equivalent 32-bit signed integer. |
| ToInt32(Byte) |
将指定的 8 位无符号整数的值转换为等效的 32 位有符号整数。Converts the value of the specified 8-bit unsigned integer to the equivalent 32-bit signed integer. |
| ToInt32(Boolean) |
将指定的布尔值转换为等效的 32 位带符号整数。Converts the specified Boolean value to the equivalent 32-bit signed integer. |
ToInt32(String)
将数字的指定字符串表示形式转换为等效的 32 位带符号整数。Converts the specified string representation of a number to an equivalent 32-bit signed integer.
public:
static int ToInt32(System::String ^ value);
public static int ToInt32 (string value);
public static int ToInt32 (string? value);
static member ToInt32 : string -> int
Public Shared Function ToInt32 (value As String) As Integer
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
一个与 value 中数字等效的 32 位带符号整数,如果 value 为 null,则为 0(零)。A 32-bit signed integer that is equivalent to the number in value, or 0 (zero) if value is null.
例外
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
下面的示例尝试将数字字符串数组中的每个元素转换为整数。The following example attempts to convert each element in a numeric string array to an integer.
string[] values = { "One", "1.34e28", "-26.87", "-18", "-6.00",
" 0", "137", "1601.9", Int32.MaxValue.ToString() };
int result;
foreach (string value in values)
{
try {
result = Convert.ToInt32(value);
Console.WriteLine("Converted the {0} value '{1}' to the {2} value {3}.",
value.GetType().Name, value, result.GetType().Name, result);
}
catch (OverflowException) {
Console.WriteLine("{0} is outside the range of the Int32 type.", value);
}
catch (FormatException) {
Console.WriteLine("The {0} value '{1}' is not in a recognizable format.",
value.GetType().Name, value);
}
}
// The example displays the following output:
// The String value 'One' is not in a recognizable format.
// The String value '1.34e28' is not in a recognizable format.
// The String value '-26.87' is not in a recognizable format.
// Converted the String value '-18' to the Int32 value -18.
// The String value '-6.00' is not in a recognizable format.
// Converted the String value ' 0' to the Int32 value 0.
// Converted the String value '137' to the Int32 value 137.
// The String value '1601.9' is not in a recognizable format.
// Converted the String value '2147483647' to the Int32 value 2147483647.
Dim values() As String = { "One", "1.34e28", "-26.87", "-18", "-6.00", _
" 0", "137", "1601.9", Int32.MaxValue.ToString() }
Dim result As Integer
For Each value As String In values
Try
result = Convert.ToInt32(value)
Console.WriteLine("Converted the {0} value '{1}' to the {2} value {3}.", _
value.GetType().Name, value, result.GetType().Name, result)
Catch e As OverflowException
Console.WriteLine("{0} is outside the range of the Int32 type.", value)
Catch e As FormatException
Console.WriteLine("The {0} value '{1}' is not in a recognizable format.", _
value.GetType().Name, value)
End Try
Next
' The example displays the following output:
' The String value 'One' is not in a recognizable format.
' The String value '1.34e28' is not in a recognizable format.
' The String value '-26.87' is not in a recognizable format.
' Converted the String value '-18' to the Int32 value -18.
' The String value '-6.00' is not in a recognizable format.
' Converted the String value ' 0' to the Int32 value 0.
' Converted the String value '137' to the Int32 value 137.
' The String value '1601.9' is not in a recognizable format.
' Converted the String value '2147483647' to the Int32 value 2147483647.
注解
使用 ToInt32(String) 方法等效于传递 value 到 Int32.Parse(String) 方法。valueUsing the ToInt32(String) method is equivalent to passing value to the Int32.Parse(String) method.value 使用当前线程区域性的格式设置约定解释 。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 Int32.TryParse 方法。If you prefer not to handle an exception if the conversion fails, you can call the Int32.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.
适用于
ToInt32(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 32 位有符号整数。Converts the value of the specified 16-bit unsigned integer to the equivalent 32-bit signed integer.
public:
static int ToInt32(System::UInt16 value);
[System.CLSCompliant(false)]
public static int ToInt32 (ushort value);
[<System.CLSCompliant(false)>]
static member ToInt32 : uint16 -> int
Public Shared Function ToInt32 (value As UShort) As Integer
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 32 位带符号整数。A 32-bit signed integer that is equivalent to value.
- 属性
示例
下面的示例将16位无符号整数数组中的每个元素转换为整数。The following example converts each element in an array of 16-bit unsigned integers to an integer.
ushort[] numbers = { UInt16.MinValue, 121, 340, UInt16.MaxValue };
int result;
foreach (ushort number in numbers)
{
try {
result = Convert.ToInt32(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 Int32 type.",
number.GetType().Name, number);
}
}
// The example displays the following output:
// Converted the UInt16 value 0 to the Int32 value 0.
// Converted the UInt16 value 121 to the Int32 value 121.
// Converted the UInt16 value 340 to the Int32 value 340.
// Converted the UInt16 value 65535 to the Int32 value 65535.
Dim numbers() As UShort = { UInt16.MinValue, 121, 340, UInt16.MaxValue }
Dim result As Integer
For Each number As UShort In numbers
Try
result = Convert.ToInt32(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 Int32 type.", _
number.GetType().Name, number)
End Try
Next
' The example displays the following output:
' Converted the UInt16 value 0 to the Int32 value 0.
' Converted the UInt16 value 121 to the Int32 value 121.
' Converted the UInt16 value 340 to the Int32 value 340.
' Converted the UInt16 value 65535 to the Int32 value 65535.
适用于
ToInt32(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 32 位有符号整数。Converts the value of the specified 32-bit unsigned integer to an equivalent 32-bit signed integer.
public:
static int ToInt32(System::UInt32 value);
[System.CLSCompliant(false)]
public static int ToInt32 (uint value);
[<System.CLSCompliant(false)>]
static member ToInt32 : uint32 -> int
Public Shared Function ToInt32 (value As UInteger) As Integer
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 32 位带符号整数。A 32-bit signed integer that is equivalent to value.
- 属性
例外
示例
下面的示例尝试将无符号整数数组中的每个元素转换为有符号整数。The following example attempts to convert each element in an array of unsigned integers to a signed integer.
uint[] numbers = { UInt32.MinValue, 121, 340, UInt32.MaxValue };
int result;
foreach (uint number in numbers)
{
try {
result = Convert.ToInt32(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 Int32 type.",
number.GetType().Name, number);
}
}
// The example displays the following output:
// Converted the UInt32 value 0 to the Int32 value 0.
// Converted the UInt32 value 121 to the Int32 value 121.
// Converted the UInt32 value 340 to the Int32 value 340.
// The UInt32 value 4294967295 is outside the range of the Int32 type.
Dim numbers() As UInteger = { UInt32.MinValue, 121, 340, UInt32.MaxValue }
Dim result As Integer
For Each number As UInteger In numbers
Try
result = Convert.ToInt32(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 Int32 type.", _
number.GetType().Name, number)
End Try
Next
' The example displays the following output:
' Converted the UInt32 value 0 to the Int32 value 0.
' Converted the UInt32 value 121 to the Int32 value 121.
' Converted the UInt32 value 340 to the Int32 value 340.
' The UInt32 value 4294967295 is outside the range of the Int32 type.
适用于
ToInt32(Single)
将指定的单精度浮点数的值转换为等效的 32 位带符号整数。Converts the value of the specified single-precision floating-point number to an equivalent 32-bit signed integer.
public:
static int ToInt32(float value);
public static int ToInt32 (float value);
static member ToInt32 : single -> int
Public Shared Function ToInt32 (value As Single) As Integer
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 32 位有符号整数。value, rounded to the nearest 32-bit signed integer. 如果 value 为两个整数中间的数字,则返回二者中的偶数;即 4.5 转换为 4,而 5.5 转换为 6。If value is halfway between two whole numbers, the even number is returned; that is, 4.5 is converted to 4, and 5.5 is converted to 6.
例外
示例
下面的示例尝试将值数组中的每个元素转换 Single 为整数。The following example attempts to convert each element in an array of Single values to an integer.
float[] values= { Single.MinValue, -1.38e10f, -1023.299f, -12.98f,
0f, 9.113e-16f, 103.919f, 17834.191f, Single.MaxValue };
int result;
foreach (float value in values)
{
try {
result = Convert.ToInt32(value);
Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.",
value.GetType().Name, value, result.GetType().Name, result);
}
catch (OverflowException) {
Console.WriteLine("{0} is outside the range of the Int32 type.", value);
}
}
// The example displays the following output:
// -3.40282346638529E+38 is outside the range of the Int32 type.
// -13799999488 is outside the range of the Int32 type.
// Converted the Double value -1023.29901123047 to the Int32 value -1023.
// Converted the Double value -12.9799995422363 to the Int32 value -13.
// Converted the Double value 0 to the Int32 value 0.
// Converted the Double value 9.11299983940444E-16 to the Int32 value 0.
// Converted the Double value 103.918998718262 to the Int32 value 104.
// Converted the Double value 17834.19140625 to the Int32 value 17834.
// 3.40282346638529E+38 is outside the range of the Int32 type.
Dim values() As Single = { Single.MinValue, -1.38e10, -1023.299, -12.98, _
0, 9.113e-16, 103.919, 17834.191, Single.MaxValue }
Dim result As Integer
For Each value As Single In values
Try
result = Convert.ToInt32(value)
Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.", _
value.GetType().Name, value, result.GetType().Name, result)
Catch e As OverflowException
Console.WriteLine("{0} is outside the range of the Int32 type.", value)
End Try
Next
' The example displays the following output:
' -3.40282346638529E+38 is outside the range of the Int32 type.
' -13799999488 is outside the range of the Int32 type.
' Converted the Double value -1023.29901123047 to the Int32 value -1023.
' Converted the Double value -12.9799995422363 to the Int32 value -13.
' Converted the Double value 0 to the Int32 value 0.
' Converted the Double value 9.11299983940444E-16 to the Int32 value 0.
' Converted the Double value 103.918998718262 to the Int32 value 104.
' Converted the Double value 17834.19140625 to the Int32 value 17834.
' 3.40282346638529E+38 is outside the range of the Int32 type.
另请参阅
适用于
ToInt32(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 32 位带符号整数。Converts the value of the specified object to a 32-bit signed integer, using the specified culture-specific formatting information.
public:
static int ToInt32(System::Object ^ value, IFormatProvider ^ provider);
public static int ToInt32 (object value, IFormatProvider provider);
public static int ToInt32 (object? value, IFormatProvider? provider);
static member ToInt32 : obj * IFormatProvider -> int
Public Shared Function ToInt32 (value As Object, provider As IFormatProvider) As Integer
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 32 位带符号整数,如果 value 为 null,则为零。A 32-bit signed integer that is equivalent to value, or zero if value is null.
例外
value 的格式不正确。value is not in an appropriate format.
value 不实现 IConvertible。value does not implement IConvertible.
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
下面的示例定义一个实现的类 IConvertible 和一个实现的类 IFormatProvider 。The following example defines a class that implements IConvertible and a class that implements IFormatProvider. 实现的类的对象 IConvertible 保存值的数组 Double 。Objects of the class that implements IConvertible hold an array of Double values. 将每个类的对象传递给 ToInt32 方法。An object of each class is passed to the ToInt32 method. 此方法 Double 使用实现的对象 IFormatProvider 来确定如何计算平均值,从而返回值数组的平均值。This method returns an average of the array of Double values, using the object that implements IFormatProvider to determine how to calculate the average.
using namespace System;
using namespace System::Collections;
// Define the types of averaging available in the class
// implementing IConvertible.
public enum class AverageType : short
{
None = 0,
GeometricMean = 1,
ArithmeticMean = 2,
Median = 3
};
// Pass an instance of this class to methods that require an
// IFormatProvider. The class instance determines the type of
// average to calculate.
ref class AverageInfo: public IFormatProvider
{
protected:
AverageType AvgType;
public:
// Specify the type of averaging in the constructor.
AverageInfo( AverageType avgType )
{
this->AvgType = avgType;
}
// This method returns a reference to the containing object
// if an object of AverageInfo type is requested.
virtual Object^ GetFormat( Type^ argType )
{
if ( argType == AverageInfo::typeid)
return this;
else
return (Object^)0;
}
property AverageType TypeOfAverage
{
// Use this property to set or get the type of averaging.
AverageType get()
{
return this->AvgType;
}
void set( AverageType value )
{
this->AvgType = value;
}
}
};
// This class encapsulates an array of double values and implements
// the IConvertible interface. Most of the IConvertible methods
// return an average of the array elements in one of three types:
// arithmetic mean, geometric mean, or median.
ref class DataSet: public IConvertible
{
private:
static Object^ null = nullptr;
protected:
ArrayList^ data;
AverageInfo^ defaultProvider;
// This method unboxes a boxed double.
double UnBoxDouble( Object^ obj )
{
return *static_cast<double^>(obj);
}
public:
// Construct the object and add an initial list of values.
// Create a default format provider.
DataSet( ... array<Double>^values )
{
data = gcnew ArrayList( (Array^)values );
defaultProvider = gcnew AverageInfo( AverageType::ArithmeticMean );
}
// Add additional values with this method.
int Add( double value )
{
data->Add( value );
return data->Count;
}
property double Item[ int ]
{
// Get, set, and add values with this indexer property.
double get( int index )
{
if ( index >= 0 && index < data->Count )
return UnBoxDouble( data[ index ] );
else
throw gcnew InvalidOperationException( "[DataSet.get] Index out of range." );
}
void set( int index, double value )
{
if ( index >= 0 && index < data->Count )
data[ index ] = value;
else
if ( index == data->Count )
data->Add( value );
else
throw gcnew InvalidOperationException( "[DataSet.set] Index out of range." );
}
}
property int Count
{
// This property returns the number of elements in the object.
int get()
{
return data->Count;
}
}
protected:
// This method calculates the average of the object's elements.
double Average( AverageType avgType )
{
double SumProd;
if ( data->Count == 0 )
return 0.0;
switch ( avgType )
{
case AverageType::GeometricMean:
SumProd = 1.0;
for ( int Index = 0; Index < data->Count; Index++ )
SumProd *= UnBoxDouble( data[ Index ] );
// This calculation will not fail with negative
// elements.
return Math::Sign( SumProd ) * Math::Pow( Math::Abs( SumProd ), 1.0 / data->Count );
case AverageType::ArithmeticMean:
SumProd = 0.0;
for ( int Index = 0; Index < data->Count; Index++ )
SumProd += UnBoxDouble( data[ Index ] );
return SumProd / data->Count;
case AverageType::Median:
if ( data->Count % 2 == 0 )
return (UnBoxDouble( data[ data->Count / 2 ] ) + UnBoxDouble( data[ data->Count / 2 - 1 ] )) / 2.0;
else
return UnBoxDouble( data[ data->Count / 2 ] );
default:
return 0.0;
}
}
// Get the AverageInfo object from the caller's format provider,
// or use the local default.
AverageInfo^ GetAverageInfo( IFormatProvider^ provider )
{
AverageInfo^ avgInfo = nullptr;
if ( provider != nullptr )
avgInfo = static_cast<AverageInfo^>(provider->GetFormat( AverageInfo::typeid ));
if ( avgInfo == nullptr )
return defaultProvider;
else
return avgInfo;
}
// Calculate the average and limit the range.
double CalcNLimitAverage( double min, double max, IFormatProvider^ provider )
{
// Get the format provider and calculate the average.
AverageInfo^ avgInfo = GetAverageInfo( provider );
double avg = Average( avgInfo->TypeOfAverage );
// Limit the range, based on the minimum and maximum values
// for the type.
return avg > max ? max : avg < min ? min : avg;
}
public:
// The following elements are required by IConvertible.
// None of these conversion functions throw exceptions. When
// the data is out of range for the type, the appropriate
// MinValue or MaxValue is used.
virtual TypeCode GetTypeCode()
{
return TypeCode::Object;
}
virtual bool ToBoolean( IFormatProvider^ provider )
{
// ToBoolean is false if the dataset is empty.
if ( data->Count <= 0 )
return false;
// For median averaging, ToBoolean is true if any
// non-discarded elements are nonzero.
else
// For median averaging, ToBoolean is true if any
// non-discarded elements are nonzero.
if ( AverageType::Median == GetAverageInfo( provider )->TypeOfAverage )
{
if ( data->Count % 2 == 0 )
return (UnBoxDouble( data[ data->Count / 2 ] ) != 0.0 || UnBoxDouble( data[ data->Count / 2 - 1 ] ) != 0.0);
else
return UnBoxDouble( data[ data->Count / 2 ] ) != 0.0;
}
// For arithmetic or geometric mean averaging, ToBoolean is
// true if any element of the dataset is nonzero.
else
{
for ( int Index = 0; Index < data->Count; Index++ )
if ( UnBoxDouble( data[ Index ] ) != 0.0 )
return true;
return false;
}
}
virtual Byte ToByte( IFormatProvider^ provider )
{
return Convert::ToByte( CalcNLimitAverage( Byte::MinValue, Byte::MaxValue, provider ) );
}
virtual Char ToChar( IFormatProvider^ provider )
{
return Convert::ToChar( Convert::ToUInt16( CalcNLimitAverage( Char::MinValue, Char::MaxValue, provider ) ) );
}
// Convert to DateTime by adding the calculated average as
// seconds to the current date and time. A valid DateTime is
// always returned.
virtual DateTime ToDateTime( IFormatProvider^ provider )
{
double seconds = Average( GetAverageInfo( provider )->TypeOfAverage );
try
{
return DateTime::Now.AddSeconds( seconds );
}
catch ( ArgumentOutOfRangeException^ )
{
return seconds < 0.0 ? DateTime::MinValue : DateTime::MaxValue;
}
}
virtual Decimal ToDecimal( IFormatProvider^ provider )
{
// The Double conversion rounds Decimal.MinValue and
// Decimal.MaxValue to invalid Decimal values, so the
// following limits must be used.
return Convert::ToDecimal( CalcNLimitAverage( -79228162514264330000000000000.0, 79228162514264330000000000000.0, provider ) );
}
virtual double ToDouble( IFormatProvider^ provider )
{
return Average( GetAverageInfo( provider )->TypeOfAverage );
}
virtual short ToInt16( IFormatProvider^ provider )
{
return Convert::ToInt16( CalcNLimitAverage( Int16::MinValue, Int16::MaxValue, provider ) );
}
virtual int ToInt32( IFormatProvider^ provider )
{
return Convert::ToInt32( CalcNLimitAverage( Int32::MinValue, Int32::MaxValue, provider ) );
}
virtual __int64 ToInt64( IFormatProvider^ provider )
{
// The Double conversion rounds Int64.MinValue and
// Int64.MaxValue to invalid Int64 values, so the following
// limits must be used.
return Convert::ToInt64( CalcNLimitAverage( -9223372036854775000, 9223372036854775000, provider ) );
}
virtual signed char ToSByte( IFormatProvider^ provider )
{
return Convert::ToSByte( CalcNLimitAverage( SByte::MinValue, SByte::MaxValue, provider ) );
}
virtual float ToSingle( IFormatProvider^ provider )
{
return Convert::ToSingle( CalcNLimitAverage( Single::MinValue, Single::MaxValue, provider ) );
}
virtual UInt16 ToUInt16( IFormatProvider^ provider )
{
return Convert::ToUInt16( CalcNLimitAverage( UInt16::MinValue, UInt16::MaxValue, provider ) );
}
virtual UInt32 ToUInt32( IFormatProvider^ provider )
{
return Convert::ToUInt32( CalcNLimitAverage( UInt32::MinValue, UInt32::MaxValue, provider ) );
}
virtual UInt64 ToUInt64( IFormatProvider^ provider )
{
// The Double conversion rounds UInt64.MaxValue to an invalid
// UInt64 value, so the following limit must be used.
return Convert::ToUInt64( CalcNLimitAverage( 0, 18446744073709550000.0, provider ) );
}
virtual Object^ ToType( Type^ conversionType, IFormatProvider^ provider )
{
return Convert::ChangeType( Average( GetAverageInfo( provider )->TypeOfAverage ), conversionType );
}
virtual String^ ToString( IFormatProvider^ provider )
{
AverageType avgType = GetAverageInfo( provider )->TypeOfAverage;
return String::Format( "( {0}: {1:G10} )", avgType, Average( avgType ) );
}
};
// Display a DataSet with three different format providers.
void DisplayDataSet( DataSet^ ds )
{
IFormatProvider^ null = nullptr;
String^ fmt = "{0,-12}{1,20}{2,20}{3,20}";
AverageInfo^ median = gcnew AverageInfo( AverageType::Median );
AverageInfo^ geMean = gcnew AverageInfo( AverageType::GeometricMean );
// Display the dataset elements.
if ( ds->Count > 0 )
{
Console::Write( "\nDataSet: [{0}", ds->Item[ 0 ] );
for ( int iX = 1; iX < ds->Count; iX++ )
Console::Write( ", {0}", ds->Item[ iX ] );
Console::WriteLine( "]\n" );
}
Console::WriteLine( fmt, "Convert::", "Default", "Geometric Mean", "Median" );
Console::WriteLine( fmt, "---------", "-------", "--------------", "------" );
Console::WriteLine( fmt, "ToBoolean", Convert::ToBoolean( ds, null ), Convert::ToBoolean( ds, geMean ), Convert::ToBoolean( ds, median ) );
Console::WriteLine( fmt, "ToByte", Convert::ToByte( ds, null ), Convert::ToByte( ds, geMean ), Convert::ToByte( ds, median ) );
Console::WriteLine( fmt, "ToChar", Convert::ToChar( ds, null ), Convert::ToChar( ds, geMean ), Convert::ToChar( ds, median ) );
Console::WriteLine( "{0,-12}{1,20:yyyy-MM-dd HH:mm:ss}"
"{2,20:yyyy-MM-dd HH:mm:ss}{3,20:yyyy-MM-dd HH:mm:ss}", "ToDateTime", Convert::ToDateTime( ds, null ), Convert::ToDateTime( ds, geMean ), Convert::ToDateTime( ds, median ) );
Console::WriteLine( fmt, "ToDecimal", Convert::ToDecimal( ds, null ), Convert::ToDecimal( ds, geMean ), Convert::ToDecimal( ds, median ) );
Console::WriteLine( fmt, "ToDouble", Convert::ToDouble( ds, null ), Convert::ToDouble( ds, geMean ), Convert::ToDouble( ds, median ) );
Console::WriteLine( fmt, "ToInt16", Convert::ToInt16( ds, null ), Convert::ToInt16( ds, geMean ), Convert::ToInt16( ds, median ) );
Console::WriteLine( fmt, "ToInt32", Convert::ToInt32( ds, null ), Convert::ToInt32( ds, geMean ), Convert::ToInt32( ds, median ) );
Console::WriteLine( fmt, "ToInt64", Convert::ToInt64( ds, null ), Convert::ToInt64( ds, geMean ), Convert::ToInt64( ds, median ) );
Console::WriteLine( fmt, "ToSByte", Convert::ToSByte( ds, null ), Convert::ToSByte( ds, geMean ), Convert::ToSByte( ds, median ) );
Console::WriteLine( fmt, "ToSingle", Convert::ToSingle( ds, null ), Convert::ToSingle( ds, geMean ), Convert::ToSingle( ds, median ) );
Console::WriteLine( fmt, "ToUInt16", Convert::ToUInt16( ds, null ), Convert::ToUInt16( ds, geMean ), Convert::ToUInt16( ds, median ) );
Console::WriteLine( fmt, "ToUInt32", Convert::ToUInt32( ds, null ), Convert::ToUInt32( ds, geMean ), Convert::ToUInt32( ds, median ) );
Console::WriteLine( fmt, "ToUInt64", Convert::ToUInt64( ds, null ), Convert::ToUInt64( ds, geMean ), Convert::ToUInt64( ds, median ) );
}
int main()
{
Console::WriteLine( "This example of the "
"Convert::To<Type>( Object*, IFormatProvider* ) methods "
"\ngenerates the following output. The example "
"displays the values \nreturned by the methods, "
"using several IFormatProvider objects.\n" );
// To call a [ParamArray] method in C++, you cannot just
// list the parameters, you need to build an array.
array<Double>^dataElem = gcnew array<Double>(6);
dataElem[ 0 ] = 10.5;
dataElem[ 1 ] = 22.2;
dataElem[ 2 ] = 45.9;
dataElem[ 3 ] = 88.7;
dataElem[ 4 ] = 156.05;
dataElem[ 5 ] = 297.6;
DataSet^ ds1 = gcnew DataSet( dataElem );
DisplayDataSet( ds1 );
dataElem = gcnew array<Double>(5);
dataElem[ 0 ] = 359999.95;
dataElem[ 1 ] = 425000;
dataElem[ 2 ] = 499999.5;
dataElem[ 3 ] = 775000;
dataElem[ 4 ] = 1695000;
DataSet^ ds2 = gcnew DataSet( dataElem );
DisplayDataSet( ds2 );
}
/*
This example of the Convert::To<Type>( Object*, IFormatProvider* ) methods
generates the following output. The example displays the values
returned by the methods, using several IFormatProvider objects.
DataSet: [10.5, 22.2, 45.9, 88.7, 156.05, 297.6]
Convert:: Default Geometric Mean Median
--------- ------- -------------- ------
ToBoolean True True True
ToByte 103 59 67
ToChar g ; C
ToDateTime 2003-05-13 15:30:23 2003-05-13 15:29:39 2003-05-13 15:29:47
ToDecimal 103.491666666667 59.4332135445164 67.3
ToDouble 103.491666666667 59.4332135445164 67.3
ToInt16 103 59 67
ToInt32 103 59 67
ToInt64 103 59 67
ToSByte 103 59 67
ToSingle 103.4917 59.43321 67.3
ToUInt16 103 59 67
ToUInt32 103 59 67
ToUInt64 103 59 67
DataSet: [359999.95, 425000, 499999.5, 775000, 1695000]
Convert:: Default Geometric Mean Median
--------- ------- -------------- ------
ToBoolean True True True
ToByte 255 255 255
ToChar ? ? ?
ToDateTime 2003-05-22 08:05:19 2003-05-20 22:54:57 2003-05-19 10:21:59
ToDecimal 750999.89 631577.237188435 499999.5
ToDouble 750999.89 631577.237188435 499999.5
ToInt16 32767 32767 32767
ToInt32 751000 631577 500000
ToInt64 751000 631577 500000
ToSByte 127 127 127
ToSingle 750999.9 631577.3 499999.5
ToUInt16 65535 65535 65535
ToUInt32 751000 631577 500000
ToUInt64 751000 631577 500000
*/
using System;
using System.Collections;
// Define the types of averaging available in the class
// implementing IConvertible.
public enum AverageType : short
{
None = 0,
GeometricMean = 1,
ArithmeticMean = 2,
Median = 3
};
// Pass an instance of this class to methods that require an
// IFormatProvider. The class instance determines the type of
// average to calculate.
public class AverageInfo : IFormatProvider
{
protected AverageType AvgType;
// Specify the type of averaging in the constructor.
public AverageInfo( AverageType avgType )
{
this.AvgType = avgType;
}
// This method returns a reference to the containing object
// if an object of AverageInfo type is requested.
public object GetFormat( Type argType )
{
if ( argType == typeof( AverageInfo ) )
return this;
else
return null;
}
// Use this property to set or get the type of averaging.
public AverageType TypeOfAverage
{
get { return this.AvgType; }
set { this.AvgType = value; }
}
}
// This class encapsulates an array of double values and implements
// the IConvertible interface. Most of the IConvertible methods
// return an average of the array elements in one of three types:
// arithmetic mean, geometric mean, or median.
public class DataSet : IConvertible
{
protected ArrayList data;
protected AverageInfo defaultProvider;
// Construct the object and add an initial list of values.
// Create a default format provider.
public DataSet( params double[ ] values )
{
data = new ArrayList( values );
defaultProvider =
new AverageInfo( AverageType.ArithmeticMean );
}
// Add additional values with this method.
public int Add( double value )
{
data.Add( value );
return data.Count;
}
// Get, set, and add values with this indexer property.
public double this[ int index ]
{
get
{
if( index >= 0 && index < data.Count )
return (double)data[ index ];
else
throw new InvalidOperationException(
"[DataSet.get] Index out of range." );
}
set
{
if( index >= 0 && index < data.Count )
data[ index ] = value;
else if( index == data.Count )
data.Add( value );
else
throw new InvalidOperationException(
"[DataSet.set] Index out of range." );
}
}
// This property returns the number of elements in the object.
public int Count
{
get { return data.Count; }
}
// This method calculates the average of the object's elements.
protected double Average( AverageType avgType )
{
double SumProd;
if( data.Count == 0 )
return 0.0;
switch( avgType )
{
case AverageType.GeometricMean:
SumProd = 1.0;
for( int Index = 0; Index < data.Count; Index++ )
SumProd *= (double)data[ Index ];
// This calculation will not fail with negative
// elements.
return Math.Sign( SumProd ) * Math.Pow(
Math.Abs( SumProd ), 1.0 / data.Count );
case AverageType.ArithmeticMean:
SumProd = 0.0;
for( int Index = 0; Index < data.Count; Index++ )
SumProd += (double)data[ Index ];
return SumProd / data.Count;
case AverageType.Median:
if( data.Count % 2 == 0 )
return ( (double)data[ data.Count / 2 ] +
(double)data[ data.Count / 2 - 1 ] ) / 2.0;
else
return (double)data[ data.Count / 2 ];
default:
return 0.0;
}
}
// Get the AverageInfo object from the caller's format provider,
// or use the local default.
protected AverageInfo GetAverageInfo( IFormatProvider provider )
{
AverageInfo avgInfo = null;
if( provider != null )
avgInfo = (AverageInfo)provider.GetFormat(
typeof( AverageInfo ) );
if ( avgInfo == null )
return defaultProvider;
else
return avgInfo;
}
// Calculate the average and limit the range.
protected double CalcNLimitAverage( double min, double max,
IFormatProvider provider )
{
// Get the format provider and calculate the average.
AverageInfo avgInfo = GetAverageInfo( provider );
double avg = Average( avgInfo.TypeOfAverage );
// Limit the range, based on the minimum and maximum values
// for the type.
return avg > max ? max : avg < min ? min : avg;
}
// The following elements are required by IConvertible.
// None of these conversion functions throw exceptions. When
// the data is out of range for the type, the appropriate
// MinValue or MaxValue is used.
public TypeCode GetTypeCode( )
{
return TypeCode.Object;
}
public bool ToBoolean( IFormatProvider provider )
{
// ToBoolean is false if the dataset is empty.
if( data.Count <= 0 )
{
return false;
}
// For median averaging, ToBoolean is true if any
// non-discarded elements are nonzero.
else if( AverageType.Median ==
GetAverageInfo( provider ).TypeOfAverage )
{
if (data.Count % 2 == 0 )
return ( (double)data[ data.Count / 2 ] != 0.0 ||
(double)data[ data.Count / 2 - 1 ] != 0.0 );
else
return (double)data[ data.Count / 2 ] != 0.0;
}
// For arithmetic or geometric mean averaging, ToBoolean is
// true if any element of the dataset is nonzero.
else
{
for( int Index = 0; Index < data.Count; Index++ )
if( (double)data[ Index ] != 0.0 )
return true;
return false;
}
}
public byte ToByte( IFormatProvider provider )
{
return Convert.ToByte( CalcNLimitAverage(
Byte.MinValue, Byte.MaxValue, provider ) );
}
public char ToChar( IFormatProvider provider )
{
return Convert.ToChar( Convert.ToUInt16( CalcNLimitAverage(
Char.MinValue, Char.MaxValue, provider ) ) );
}
// Convert to DateTime by adding the calculated average as
// seconds to the current date and time. A valid DateTime is
// always returned.
public DateTime ToDateTime( IFormatProvider provider )
{
double seconds =
Average( GetAverageInfo( provider ).TypeOfAverage );
try
{
return DateTime.Now.AddSeconds( seconds );
}
catch( ArgumentOutOfRangeException )
{
return seconds < 0.0 ? DateTime.MinValue : DateTime.MaxValue;
}
}
public decimal ToDecimal( IFormatProvider provider )
{
// The Double conversion rounds Decimal.MinValue and
// Decimal.MaxValue to invalid Decimal values, so the
// following limits must be used.
return Convert.ToDecimal( CalcNLimitAverage(
-79228162514264330000000000000.0,
79228162514264330000000000000.0, provider ) );
}
public double ToDouble( IFormatProvider provider )
{
return Average( GetAverageInfo(provider).TypeOfAverage );
}
public short ToInt16( IFormatProvider provider )
{
return Convert.ToInt16( CalcNLimitAverage(
Int16.MinValue, Int16.MaxValue, provider ) );
}
public int ToInt32( IFormatProvider provider )
{
return Convert.ToInt32( CalcNLimitAverage(
Int32.MinValue, Int32.MaxValue, provider ) );
}
public long ToInt64( IFormatProvider provider )
{
// The Double conversion rounds Int64.MinValue and
// Int64.MaxValue to invalid Int64 values, so the following
// limits must be used.
return Convert.ToInt64( CalcNLimitAverage(
-9223372036854775000, 9223372036854775000, provider ) );
}
public SByte ToSByte( IFormatProvider provider )
{
return Convert.ToSByte( CalcNLimitAverage(
SByte.MinValue, SByte.MaxValue, provider ) );
}
public float ToSingle( IFormatProvider provider )
{
return Convert.ToSingle( CalcNLimitAverage(
Single.MinValue, Single.MaxValue, provider ) );
}
public UInt16 ToUInt16( IFormatProvider provider )
{
return Convert.ToUInt16( CalcNLimitAverage(
UInt16.MinValue, UInt16.MaxValue, provider ) );
}
public UInt32 ToUInt32( IFormatProvider provider )
{
return Convert.ToUInt32( CalcNLimitAverage(
UInt32.MinValue, UInt32.MaxValue, provider ) );
}
public UInt64 ToUInt64( IFormatProvider provider )
{
// The Double conversion rounds UInt64.MaxValue to an invalid
// UInt64 value, so the following limit must be used.
return Convert.ToUInt64( CalcNLimitAverage(
0, 18446744073709550000.0, provider ) );
}
public object ToType( Type conversionType,
IFormatProvider provider )
{
return Convert.ChangeType( Average(
GetAverageInfo( provider ).TypeOfAverage ),
conversionType );
}
public string ToString( IFormatProvider provider )
{
AverageType avgType = GetAverageInfo( provider ).TypeOfAverage;
return String.Format( "( {0}: {1:G10} )", avgType,
Average( avgType ) );
}
}
class IConvertibleProviderDemo
{
// Display a DataSet with three different format providers.
public static void DisplayDataSet( DataSet ds )
{
string fmt = "{0,-12}{1,20}{2,20}{3,20}";
AverageInfo median = new AverageInfo( AverageType.Median );
AverageInfo geMean =
new AverageInfo( AverageType.GeometricMean );
// Display the dataset elements.
if( ds.Count > 0 )
{
Console.Write( "\nDataSet: [{0}", ds[ 0 ] );
for( int iX = 1; iX < ds.Count; iX++ )
Console.Write( ", {0}", ds[ iX ] );
Console.WriteLine( "]\n" );
}
Console.WriteLine( fmt, "Convert.", "Default",
"Geometric Mean", "Median");
Console.WriteLine( fmt, "--------", "-------",
"--------------", "------");
Console.WriteLine( fmt, "ToBoolean",
Convert.ToBoolean( ds, null ),
Convert.ToBoolean( ds, geMean ),
Convert.ToBoolean( ds, median ) );
Console.WriteLine( fmt, "ToByte",
Convert.ToByte( ds, null ),
Convert.ToByte( ds, geMean ),
Convert.ToByte( ds, median ) );
Console.WriteLine( fmt, "ToChar",
Convert.ToChar( ds, null ),
Convert.ToChar( ds, geMean ),
Convert.ToChar( ds, median ) );
Console.WriteLine( "{0,-12}{1,20:yyyy-MM-dd HH:mm:ss}" +
"{2,20:yyyy-MM-dd HH:mm:ss}{3,20:yyyy-MM-dd HH:mm:ss}",
"ToDateTime", Convert.ToDateTime( ds, null ),
Convert.ToDateTime( ds, geMean ),
Convert.ToDateTime( ds, median ) );
Console.WriteLine( fmt, "ToDecimal",
Convert.ToDecimal( ds, null ),
Convert.ToDecimal( ds, geMean ),
Convert.ToDecimal( ds, median ) );
Console.WriteLine( fmt, "ToDouble",
Convert.ToDouble( ds, null ),
Convert.ToDouble( ds, geMean ),
Convert.ToDouble( ds, median ) );
Console.WriteLine( fmt, "ToInt16",
Convert.ToInt16( ds, null ),
Convert.ToInt16( ds, geMean ),
Convert.ToInt16( ds, median ) );
Console.WriteLine( fmt, "ToInt32",
Convert.ToInt32( ds, null ),
Convert.ToInt32( ds, geMean ),
Convert.ToInt32( ds, median ) );
Console.WriteLine( fmt, "ToInt64",
Convert.ToInt64( ds, null ),
Convert.ToInt64( ds, geMean ),
Convert.ToInt64( ds, median ) );
Console.WriteLine( fmt, "ToSByte",
Convert.ToSByte( ds, null ),
Convert.ToSByte( ds, geMean ),
Convert.ToSByte( ds, median ) );
Console.WriteLine( fmt, "ToSingle",
Convert.ToSingle( ds, null ),
Convert.ToSingle( ds, geMean ),
Convert.ToSingle( ds, median ) );
Console.WriteLine( fmt, "ToUInt16",
Convert.ToUInt16( ds, null ),
Convert.ToUInt16( ds, geMean ),
Convert.ToUInt16( ds, median ) );
Console.WriteLine( fmt, "ToUInt32",
Convert.ToUInt32( ds, null ),
Convert.ToUInt32( ds, geMean ),
Convert.ToUInt32( ds, median ) );
Console.WriteLine( fmt, "ToUInt64",
Convert.ToUInt64( ds, null ),
Convert.ToUInt64( ds, geMean ),
Convert.ToUInt64( ds, median ) );
}
public static void Main( )
{
Console.WriteLine( "This example of " +
"the Convert.To<Type>( object, IFormatProvider ) methods " +
"\ngenerates the following output. The example " +
"displays the values \nreturned by the methods, " +
"using several IFormatProvider objects.\n" );
DataSet ds1 = new DataSet(
10.5, 22.2, 45.9, 88.7, 156.05, 297.6 );
DisplayDataSet( ds1 );
DataSet ds2 = new DataSet(
359999.95, 425000, 499999.5, 775000, 1695000 );
DisplayDataSet( ds2 );
}
}
/*
This example of the Convert.To<Type>( object, IFormatProvider ) methods
generates the following output. The example displays the values
returned by the methods, using several IFormatProvider objects.
DataSet: [10.5, 22.2, 45.9, 88.7, 156.05, 297.6]
Convert. Default Geometric Mean Median
-------- ------- -------------- ------
ToBoolean True True True
ToByte 103 59 67
ToChar g ; C
ToDateTime 2003-05-13 15:04:12 2003-05-13 15:03:28 2003-05-13 15:03:35
ToDecimal 103.491666666667 59.4332135445164 67.3
ToDouble 103.491666666667 59.4332135445164 67.3
ToInt16 103 59 67
ToInt32 103 59 67
ToInt64 103 59 67
ToSByte 103 59 67
ToSingle 103.4917 59.43321 67.3
ToUInt16 103 59 67
ToUInt32 103 59 67
ToUInt64 103 59 67
DataSet: [359999.95, 425000, 499999.5, 775000, 1695000]
Convert. Default Geometric Mean Median
-------- ------- -------------- ------
ToBoolean True True True
ToByte 255 255 255
ToChar ? ? ?
ToDateTime 2003-05-22 07:39:08 2003-05-20 22:28:45 2003-05-19 09:55:48
ToDecimal 750999.89 631577.237188435 499999.5
ToDouble 750999.89 631577.237188435 499999.5
ToInt16 32767 32767 32767
ToInt32 751000 631577 500000
ToInt64 751000 631577 500000
ToSByte 127 127 127
ToSingle 750999.9 631577.3 499999.5
ToUInt16 65535 65535 65535
ToUInt32 751000 631577 500000
ToUInt64 751000 631577 500000
*/
Imports System.Collections
Module IConvertibleProviderDemo
' Define the types of averaging available in the class
' implementing IConvertible.
Enum AverageType as Short
None = 0
GeometricMean = 1
ArithmeticMean = 2
Median = 3
End Enum
' Pass an instance of this class to methods that require an
' IFormatProvider. The class instance determines the type of
' average to calculate.
Public Class AverageInfo
Implements IFormatProvider
Protected AvgType As AverageType
' Specify the type of averaging in the constructor.
Public Sub New( avgType As AverageType )
Me.AvgType = avgType
End Sub
' This method returns a reference to the containing object
' if an object of AverageInfo type is requested.
Public Function GetFormat( argType As Type ) As Object _
Implements IFormatProvider.GetFormat
If argType Is GetType( AverageInfo ) Then
Return Me
Else
Return Nothing
End If
End Function
' Use this property to set or get the type of averaging.
Public Property TypeOfAverage( ) As AverageType
Get
Return Me.AvgType
End Get
Set( ByVal value as AverageType )
Me.AvgType = value
End Set
End Property
End Class
' This class encapsulates an array of Double values and implements
' the IConvertible interface. Most of the IConvertible methods
' return an average of the array elements in one of three types:
' arithmetic mean, geometric mean, or median.
Public Class DataSet
Implements IConvertible
Protected data As ArrayList
Protected defaultProvider As AverageInfo
' Construct the object and add an initial list of values.
' Create a default format provider.
Public Sub New( ParamArray values( ) As Double )
data = New ArrayList( values )
defaultProvider = New AverageInfo( _
AverageType.ArithmeticMean )
End Sub
' Add additional values with this method.
Public Function Add( value As Double ) As Integer
data.Add( value )
Return data.Count
End Function
' Get, set, and add values with this indexer property.
Default Public Property Item(index As Integer) As Double
Get
If index >= 0 AndAlso index < data.Count Then
Return System.Convert.ToDouble( data( index ) )
Else
Throw New InvalidOperationException( _
"[DataSet.get] Index out of range." )
End If
End Get
Set
If index >= 0 AndAlso index < data.Count Then
data( index ) = value
ElseIf index = data.Count Then
data.Add( value )
Else
Throw New InvalidOperationException( _
"[DataSet.set] Index out of range." )
End If
End Set
End Property
' This property returns the number of elements in the object.
Public ReadOnly Property Count( ) As Integer
Get
Return data.Count
End Get
End Property
' This method calculates the average of the object's elements.
Protected Function Average( ByVal avgType As AverageType ) As Double
Dim SumProd As Double
Dim Index As Integer
If data.Count = 0 Then Return 0.0
Select Case avgType
Case AverageType.GeometricMean
SumProd = 1.0
For Index = 0 To data.Count - 1
SumProd *= data( Index )
Next Index
' This calculation will not fail with negative
' elements.
Return Math.Sign( SumProd ) * Math.Pow( _
Math.Abs( SumProd ), 1.0 / data.Count )
Case AverageType.ArithmeticMean
SumProd = 0.0
For Index = 0 To data.Count - 1
SumProd += data( Index )
Next Index
Return SumProd / data.Count
Case AverageType.Median
If data.Count Mod 2 = 0 Then
Return ( data( data.Count \ 2 ) + _
data( data.Count \ 2 - 1 ) ) / 2.0
Else
Return data( data.Count \ 2 )
End If
End Select
End Function
' Get the AverageInfo object from the caller's format
' provider, or use the local default.
Protected Function GetAverageInfo( _
provider As IFormatProvider ) As AverageInfo
Dim avgInfo As AverageInfo = Nothing
If Not provider Is Nothing Then
avgInfo = provider.GetFormat( GetType( AverageInfo ) )
End If
Return IIf( avgInfo Is Nothing, defaultProvider, avgInfo )
End Function
' Calculate the average and limit the range.
Protected Function CalcNLimitAverage( min As Double, _
max As Double, provider as IFormatProvider ) As Double
' Get the format provider and calculate the average.
Dim avgInfo As AverageInfo = GetAverageInfo( provider )
Dim avg As Double = Average( avgInfo.TypeOfAverage )
' Limit the range, based on the minimum and maximum values
' for the type.
Return IIf( avg > max, max, IIf( avg < min, min, avg ) )
End Function
' The following elements are required by IConvertible.
' None of these conversion functions throw exceptions. When
' the data is out of range for the type, the appropriate
' MinValue or MaxValue is used.
Public Function GetTypeCode( ) As TypeCode _
Implements IConvertible.GetTypeCode
Return TypeCode.Object
End Function
Function ToBoolean( ByVal provider As IFormatProvider ) As _
Boolean Implements IConvertible.ToBoolean
' ToBoolean is false if the dataset is empty.
If data.Count <= 0 Then
Return False
' For median averaging, ToBoolean is true if any
' non-discarded elements are nonzero.
ElseIf AverageType.Median = _
GetAverageInfo( provider ).TypeOfAverage Then
If data.Count Mod 2 = 0 Then
Return ( data( data.Count \ 2 ) <> 0.0 Or _
data( data.Count \ 2 - 1 ) <> 0.0 )
Else
Return data( data.Count \ 2 ) <> 0.0
End If
' For arithmetic or geometric mean averaging, ToBoolean is
' true if any element of the dataset is nonzero.
Else
Dim Index As Integer
For Index = 0 To data.Count - 1
If data( Index ) <> 0.0 Then Return True
Next Index
Return False
End If
End Function
Function ToByte( ByVal provider As IFormatProvider ) As Byte _
Implements IConvertible.ToByte
Return Convert.ToByte( CalcNLimitAverage( _
Byte.MinValue, Byte.MaxValue, provider ) )
End Function
Function ToChar( ByVal provider As IFormatProvider ) As Char _
Implements IConvertible.ToChar
Return Convert.ToChar( Convert.ToUInt16( _
CalcNLimitAverage( 0.0, &HFFFF, provider ) ) )
End Function
' Convert to DateTime by adding the calculated average as
' seconds to the current date and time. A valid DateTime is
' always returned.
Function ToDateTime( ByVal provider As IFormatProvider ) As _
DateTime Implements IConvertible.ToDateTime
Dim seconds As Double = Average( _
GetAverageInfo( provider ).TypeOfAverage )
Try
Return DateTime.Now.AddSeconds( seconds )
Catch ex As ArgumentOutOfRangeException
Return IIf( seconds < 0.0, DateTime.MinValue, _
DateTime.MaxValue )
End Try
End Function
Function ToDecimal( ByVal provider As IFormatProvider ) As _
Decimal Implements IConvertible.ToDecimal
' The Double conversion rounds Decimal.MinValue and
' Decimal.MaxValue to invalid Decimal values, so the
' following limits must be used.
Return Convert.ToDecimal( CalcNLimitAverage( _
-79228162514264330000000000000.0, _
79228162514264330000000000000.0, provider ) )
End Function
Function ToDouble( ByVal provider As IFormatProvider) As _
Double Implements IConvertible.ToDouble
Return Average( GetAverageInfo( provider ).TypeOfAverage )
End Function
Function ToInt16( ByVal provider As IFormatProvider ) As _
Short Implements IConvertible.ToInt16
Return Convert.ToInt16( CalcNLimitAverage( _
Int16.MinValue, Int16.MaxValue, provider ) )
End Function
Function ToInt32( ByVal provider As IFormatProvider ) As _
Integer Implements IConvertible.ToInt32
Return Convert.ToInt32( CalcNLimitAverage( _
Int32.MinValue, Int32.MaxValue, provider ) )
End Function
Function ToInt64( ByVal provider As IFormatProvider ) As Long _
Implements IConvertible.ToInt64
' The Double conversion rounds Int64.MinValue and
' Int64.MaxValue to invalid Long values, so the following
' limits must be used.
Return Convert.ToInt64( CalcNLimitAverage( _
-9223372036854775000, 9223372036854775000, provider ) )
End Function
Function ToSByte( ByVal provider As IFormatProvider ) As _
SByte Implements IConvertible.ToSByte
' SByte.MinValue and SByte.MaxValue are not defined in
' Visual Basic.
Return Convert.ToSByte( CalcNLimitAverage( _
-128, 127, provider ) )
End Function
Function ToSingle( ByVal provider As IFormatProvider ) As _
Single Implements IConvertible.ToSingle
Return Convert.ToSingle( CalcNLimitAverage( _
Single.MinValue, Single.MaxValue, provider ) )
End Function
Function ToUInt16( ByVal provider As IFormatProvider ) As _
UInt16 Implements IConvertible.ToUInt16
' UInt16.MinValue and UInt16.MaxValue are not defined in
' Visual Basic.
Return Convert.ToUInt16( CalcNLimitAverage( _
0, &HFFFF, provider ) )
End Function
Function ToUInt32( ByVal provider As IFormatProvider ) As _
UInt32 Implements IConvertible.ToUInt32
' UInt32.MinValue and UInt32.MaxValue are not defined in
' Visual Basic.
Return Convert.ToUInt32( CalcNLimitAverage( _
0, 4294967295, provider ) )
End Function
Function ToUInt64( ByVal provider As IFormatProvider ) As _
UInt64 Implements IConvertible.ToUInt64
' UInt64.MinValue and UInt64.MaxValue are not defined in
' Visual Basic. The Double conversion would have rounded
' UInt64.MaxValue, so the following limit must be used.
Return Convert.ToUInt64( CalcNLimitAverage( _
0, 18446744073709550000.0, provider ) )
End Function
Function ToType( ByVal conversionType As Type, _
ByVal provider As IFormatProvider) As Object _
Implements IConvertible.ToType
Return Convert.ChangeType( Average( GetAverageInfo( _
provider ).TypeOfAverage ), conversionType )
End Function
Overloads Function ToString( ByVal provider As IFormatProvider _
) As String Implements IConvertible.ToString
Dim avgType as AverageType = _
GetAverageInfo( provider ).TypeOfAverage
Return String.Format( "( {0}: {1:G10} )", avgType, _
Average( avgType ) )
End Function
End Class
' Display a DataSet with three different format providers.
Sub DisplayDataSet( ds As DataSet )
Dim fmt As String = "{0,-12}{1,20}{2,20}{3,20}"
Dim median As AverageInfo = New AverageInfo( AverageType.Median )
Dim geMean As AverageInfo = _
New AverageInfo( AverageType.GeometricMean )
Dim iX As Integer
' Display the dataset elements.
If ds.Count > 0 Then
Console.Write( vbCrLf & "DataSet: [{0}", ds( 0 ) )
For iX = 1 To ds.Count - 1
Console.Write( ", {0}", ds( iX ) )
Next iX
Console.WriteLine( "]" & vbCrLf )
End If
Console.WriteLine( fmt, "Convert.", "Default", _
"Geometric Mean", "Median" )
Console.WriteLine( fmt, "--------", "-------", _
"--------------", "------" )
Console.WriteLine( fmt, "ToBoolean", _
Convert.ToBoolean( ds, Nothing ), _
Convert.ToBoolean( ds, geMean ), _
Convert.ToBoolean( ds, median ) )
Console.WriteLine( fmt, "ToByte", _
Convert.ToByte( ds, Nothing ), _
Convert.ToByte( ds, geMean ), _
Convert.ToByte( ds, median ) )
Console.WriteLine( fmt, "ToChar", _
Convert.ToChar( ds, Nothing ), _
Convert.ToChar( ds, geMean ), _
Convert.ToChar( ds, median ) )
Console.WriteLine( "{0,-12}{1,20:yyyy-MM-dd HH:mm:ss}" & _
"{2,20:yyyy-MM-dd HH:mm:ss}{3,20:yyyy-MM-dd HH:mm:ss}", _
"ToDateTime", Convert.ToDateTime( ds, Nothing ), _
Convert.ToDateTime( ds, geMean ), _
Convert.ToDateTime( ds, median ) )
Console.WriteLine( fmt, "ToDecimal", _
Convert.ToDecimal( ds, Nothing ), _
Convert.ToDecimal( ds, geMean ), _
Convert.ToDecimal( ds, median ) )
Console.WriteLine( fmt, "ToDouble", _
Convert.ToDouble( ds, Nothing ), _
Convert.ToDouble( ds, geMean ), _
Convert.ToDouble( ds, median ) )
Console.WriteLine( fmt, "ToInt16", _
Convert.ToInt16( ds, Nothing ), _
Convert.ToInt16( ds, geMean ), _
Convert.ToInt16( ds, median ) )
Console.WriteLine( fmt, "ToInt32", _
Convert.ToInt32( ds, Nothing ), _
Convert.ToInt32( ds, geMean ), _
Convert.ToInt32( ds, median ) )
Console.WriteLine( fmt, "ToInt64", _
Convert.ToInt64( ds, Nothing ), _
Convert.ToInt64( ds, geMean ), _
Convert.ToInt64( ds, median ) )
Console.WriteLine( fmt, "ToSByte", _
Convert.ToSByte( ds, Nothing ), _
Convert.ToSByte( ds, geMean ), _
Convert.ToSByte( ds, median ) )
Console.WriteLine( fmt, "ToSingle", _
Convert.ToSingle( ds, Nothing ), _
Convert.ToSingle( ds, geMean ), _
Convert.ToSingle( ds, median ) )
Console.WriteLine( fmt, "ToUInt16", _
Convert.ToUInt16( ds, Nothing ), _
Convert.ToUInt16( ds, geMean ), _
Convert.ToUInt16( ds, median ) )
Console.WriteLine( fmt, "ToUInt32", _
Convert.ToUInt32( ds, Nothing ), _
Convert.ToUInt32( ds, geMean ), _
Convert.ToUInt32( ds, median ) )
Console.WriteLine( fmt, "ToUInt64", _
Convert.ToUInt64( ds, Nothing ), _
Convert.ToUInt64( ds, geMean ), _
Convert.ToUInt64( ds, median ) )
End Sub
Sub Main( )
Console.WriteLine( _
"This example of the Convert.To<Type>( Object, " & _
"IFormatProvider ) methods " & vbCrLf & "generates " & _
"the following output. The example displays the " & _
"values " & vbCrLf & "returned by the methods, " & _
"using several IFormatProvider objects." & vbCrLf )
Dim ds1 As New DataSet( 10.5, 22.2, 45.9, 88.7, 156.05, 297.6 )
DisplayDataSet( ds1 )
Dim ds2 As New DataSet( _
359999.95, 425000, 499999.5, 775000, 1695000 )
DisplayDataSet( ds2 )
End Sub
End Module
' This example of the Convert.To<Type>( Object, IFormatProvider ) methods
' generates the following output. The example displays the values
' returned by the methods, using several IFormatProvider objects.
'
' DataSet: [10.5, 22.2, 45.9, 88.7, 156.05, 297.6]
'
' Convert. Default Geometric Mean Median
' -------- ------- -------------- ------
' ToBoolean True True True
' ToByte 103 59 67
' ToChar g ; C
' ToDateTime 2003-05-13 14:52:53 2003-05-13 14:52:09 2003-05-13 14:52:17
' ToDecimal 103.491666666667 59.4332135445164 67.3
' ToDouble 103.491666666667 59.4332135445164 67.3
' ToInt16 103 59 67
' ToInt32 103 59 67
' ToInt64 103 59 67
' ToSByte 103 59 67
' ToSingle 103.4917 59.43321 67.3
' ToUInt16 103 59 67
' ToUInt32 103 59 67
' ToUInt64 103 59 67
'
' DataSet: [359999.95, 425000, 499999.5, 775000, 1695000]
'
' Convert. Default Geometric Mean Median
' -------- ------- -------------- ------
' ToBoolean True True True
' ToByte 255 255 255
' ToChar ? ? ?
' ToDateTime 2003-05-22 07:27:49 2003-05-20 22:17:27 2003-05-19 09:44:29
' ToDecimal 750999.89 631577.237188435 499999.5
' ToDouble 750999.89 631577.237188435 499999.5
' ToInt16 32767 32767 32767
' ToInt32 751000 631577 500000
' ToInt64 751000 631577 500000
' ToSByte 127 127 127
' ToSingle 750999.9 631577.3 499999.5
' ToUInt16 65535 65535 65535
' ToUInt32 751000 631577 500000
' ToUInt64 751000 631577 500000
注解
返回值是调用的 IConvertible.ToInt32 基础类型的方法的结果 value 。The return value is the result of invoking the IConvertible.ToInt32 method of the underlying type of value.
provider 使用户能够指定有关的内容的特定于区域性的转换信息 value 。provider enables the user to specify culture-specific conversion information about the contents of value. 例如,如果 value 是表示数字的,则 String provider 可能提供有关用于表示该数字的表示法的区域性特定信息。For example, if value is a String that represents a number, provider could supply culture-specific information about the notation used to represent that number.
基类型将忽略 provider ; 但是,如果 value 是实现接口的用户定义类型,则可以使用参数 IConvertible 。The base types ignore provider; however, the parameter may be used if value is a user-defined type that implements the IConvertible interface.
适用于
ToInt32(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 32 位带符号整数。Converts the specified string representation of a number to an equivalent 32-bit signed integer, using the specified culture-specific formatting information.
public:
static int ToInt32(System::String ^ value, IFormatProvider ^ provider);
public static int ToInt32 (string value, IFormatProvider provider);
public static int ToInt32 (string? value, IFormatProvider? provider);
static member ToInt32 : string * IFormatProvider -> int
Public Shared Function ToInt32 (value As String, provider As IFormatProvider) As Integer
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 中数字等效的 32 位带符号整数,如果 value 为 null,则为 0(零)。A 32-bit signed integer that is equivalent to the number in value, or 0 (zero) if value is null.
例外
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
下面的示例定义了一个自定义 NumberFormatInfo 对象,该对象将字符串 "pos" 识别为正号,将字符串 "neg" 识别为负号。The following example defines a custom NumberFormatInfo object that recognizes the string "pos" as the positive sign and the string "neg" as the negative sign. 然后,它会使用此提供程序和固定区域性的提供程序尝试将数值字符串数组的每个元素转换为整数 NumberFormatInfo 。It then attempts to convert each element of a numeric string array to an integer using both this provider and the NumberFormatInfo provider for the invariant culture.
using System;
using System.Globalization;
public class Example
{
public static void Main()
{
// Create a custom NumberFormatInfo object and set its two properties
// used by default in parsing numeric strings.
NumberFormatInfo customProvider = new NumberFormatInfo();
customProvider.NegativeSign = "neg ";
customProvider.PositiveSign = "pos ";
// Add custom and invariant provider to an array of providers.
NumberFormatInfo[] providers = { customProvider, NumberFormatInfo.InvariantInfo };
// Define an array of strings to convert.
string[] numericStrings = { "123456789", "+123456789", "pos 123456789",
"-123456789", "neg 123456789", "123456789.",
"123,456,789", "(123456789)", "2147483648",
"-2147483649" };
// Use each provider to parse all the numeric strings.
for (int ctr = 0; ctr <= 1; ctr++)
{
IFormatProvider provider = providers[ctr];
Console.WriteLine(ctr == 0 ? "Custom Provider:" : "Invariant Provider:");
foreach (string numericString in numericStrings)
{
Console.Write("{0,15} --> ", numericString);
try {
Console.WriteLine("{0,20}", Convert.ToInt32(numericString, provider));
}
catch (FormatException) {
Console.WriteLine("{0,20}", "FormatException");
}
catch (OverflowException) {
Console.WriteLine("{0,20}", "OverflowException");
}
}
Console.WriteLine();
}
}
}
// The example displays the following output:
// Custom Provider:
// 123456789 --> 123456789
// +123456789 --> FormatException
// pos 123456789 --> 123456789
// -123456789 --> FormatException
// neg 123456789 --> -123456789
// 123456789. --> FormatException
// 123,456,789 --> FormatException
// (123456789) --> FormatException
// 2147483648 --> OverflowException
// -2147483649 --> FormatException
//
// Invariant Provider:
// 123456789 --> 123456789
// +123456789 --> 123456789
// pos 123456789 --> FormatException
// -123456789 --> -123456789
// neg 123456789 --> FormatException
// 123456789. --> FormatException
// 123,456,789 --> FormatException
// (123456789) --> FormatException
// 2147483648 --> OverflowException
// -2147483649 --> OverflowException
Imports System.Globalization
Module Example
Public Sub Main()
' Create a custom NumberFormatInfo object and set its two properties
' used by default in parsing numeric strings.
Dim customProvider As New NumberFormatInfo()
customProvider.NegativeSign = "neg "
customProvider.PositiveSign = "pos "
' Add custom and invariant provider to an array of providers.
Dim providers() As NumberFormatInfo = { customProvider, NumberFormatInfo.InvariantInfo }
' Define an array of strings to convert.
Dim numericStrings() As String = { "123456789", "+123456789", "pos 123456789", _
"-123456789", "neg 123456789", "123456789.", _
"123,456,789", "(123456789)", "2147483648", _
"-2147483649" }
' Use each provider to parse all the numeric strings.
For ctr As Integer = 0 To 1
Dim provider As IFormatPRovider = providers(ctr)
Console.WriteLine(IIf(ctr = 0, "Custom Provider:", "Invariant Provider:"))
For Each numericString As String In numericStrings
Console.Write("{0,15} --> ", numericString)
Try
Console.WriteLine("{0,20}", Convert.ToInt32(numericString, provider))
Catch e As FormatException
Console.WriteLine("{0,20}", "FormatException")
Catch e As OverflowException
Console.WriteLine("{0,20}", "OverflowException")
End Try
Next
Console.WriteLine()
Next
End Sub
End Module
' The example displays the following output:
' Custom Provider:
' 123456789 --> 123456789
' +123456789 --> FormatException
' pos 123456789 --> 123456789
' -123456789 --> FormatException
' neg 123456789 --> -123456789
' 123456789. --> FormatException
' 123,456,789 --> FormatException
' (123456789) --> FormatException
' 2147483648 --> OverflowException
' -2147483649 --> FormatException
'
' Invariant Provider:
' 123456789 --> 123456789
' +123456789 --> 123456789
' pos 123456789 --> FormatException
' -123456789 --> -123456789
' neg 123456789 --> FormatException
' 123456789. --> FormatException
' 123,456,789 --> FormatException
' (123456789) --> FormatException
' 2147483648 --> OverflowException
' -2147483649 --> OverflowException
注解
返回值是对调用方法的结果 Int32.Parse value 。The return value is the result of invoking the Int32.Parse method on value.
provider 是一个 IFormatProvider 获取对象的实例 NumberFormatInfo 。provider is an IFormatProvider instance that obtains a NumberFormatInfo object. NumberFormatInfo对象提供有关的格式的区域性特定信息 value 。The NumberFormatInfo object provides culture-specific information about the format of value. 如果 provider 为 null ,则 NumberFormatInfo 使用当前区域性的。If provider is null, the NumberFormatInfo for the current culture is used.
如果你不希望在转换失败时处理异常,则可以改为调用 Int32.TryParse 方法。If you prefer not to handle an exception if the conversion fails, you can call the Int32.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.
适用于
ToInt32(String, Int32)
将指定基数的数字的字符串表示形式转换为等效的 32 位有符号整数。Converts the string representation of a number in a specified base to an equivalent 32-bit signed integer.
public:
static int ToInt32(System::String ^ value, int fromBase);
public static int ToInt32 (string value, int fromBase);
public static int ToInt32 (string? value, int fromBase);
static member ToInt32 : string * int -> int
Public Shared Function ToInt32 (value As String, fromBase As Integer) As Integer
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
一个与 value 中数字等效的 32 位带符号整数,如果 value 为 null,则为 0(零)。A 32-bit signed integer that is equivalent to the number in value, or 0 (zero) if value is null.
例外
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.
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.
注解
如果 fromBase 为16,则可以为参数指定的数字加上 value "0x" 或 "0x" 作为前缀。If fromBase is 16, you can prefix the number specified by the value parameter with "0x" or "0X".
由于非基数10数值表示形式不支持负号,因此该 ToInt32(String, Int32) 方法假设负数使用两个的补码表示形式。Because the negative sign is not supported for non-base 10 numeric representations, the ToInt32(String, Int32) method assumes that negative numbers use two's complement representation. 换言之,该方法始终将整数 (位 31) 的最高顺序二进制位解释为其符号位。In other words, the method always interprets the highest-order binary bit of an integer (bit 31) as its sign bit. 因此,可以编写代码,在此代码中,在 Int32 Int32 不引发异常的情况下,将不在数据类型范围内的非 base 10 数字转换为值。As a result, it is possible to write code in which a non-base 10 number that is out of the range of the Int32 data type is converted to an Int32 value without the method throwing an exception. 下面的示例 Int32.MaxValue 按1递增,将得到的数字转换为其十六进制字符串表示形式,然后调用 ToInt32(String, Int32) 方法。The following example increments Int32.MaxValue by one, converts the resulting number to its hexadecimal string representation, and then calls the ToInt32(String, Int32) method. 方法会显示消息 "0x80000000 转换为-2147483648",而不是引发异常。Instead of throwing an exception, the method displays the message, "0x80000000 converts to -2147483648."
// Create a hexadecimal value out of range of the integer type.
String^ value1 = Convert::ToString((static_cast<__int64>(int::MaxValue)) + 1, 16);
// Convert it back to a number.
try {
int number = Convert::ToInt32(value1, 16);
Console::WriteLine("0x{0} converts to {1}.", value1, number);
}
catch (OverflowException ^e) {
Console::WriteLine("Unable to convert '0x{0}' to an integer.", value1);
}
// The example displays the following output:
// 0x80000000 converts to -2147483648.
// Create a hexadecimal value out of range of the Integer type.
string value = Convert.ToString((long) int.MaxValue + 1, 16);
// Convert it back to a number.
try
{
int number = Convert.ToInt32(value, 16);
Console.WriteLine("0x{0} converts to {1}.", value, number.ToString());
}
catch (OverflowException)
{
Console.WriteLine("Unable to convert '0x{0}' to an integer.", value);
}
' Create a hexadecimal value out of range of the Integer type.
Dim value As String = Convert.ToString(CLng(Integer.MaxValue) + 1, 16)
' Convert it back to a number.
Try
Dim number As Integer = Convert.ToInt32(value, 16)
Console.WriteLine("0x{0} converts to {1}.", value, number)
Catch e As OverflowException
Console.WriteLine("Unable to convert '0x{0}' to an integer.", value)
End Try
执行二元运算或数值转换时,开发人员始终负责验证方法是否使用适当的数值表示形式来解释特定值。When performing binary operations or numeric conversions, it is always the responsibility of the developer to verify that a method is using the appropriate numeric representation to interpret a particular value. 如下面的示例所示,通过先检索数值的符号,然后将其转换为十六进制字符串表示形式,可以确保方法适当地处理溢出。As the following example illustrates, you can ensure that the method handles overflows appropriately by first retrieving the sign of the numeric value before converting it to its hexadecimal string representation. 如果原始值为正值,但转换回整数产生负值,则引发异常。Throw an exception if the original value was positive but the conversion back to an integer yields a negative value.
__int64 sourceNumber2 = (static_cast<__int64>(int::MaxValue)) + 1;
bool isNegative = Math::Sign(sourceNumber2) == -1;
String^ value2 = Convert::ToString(sourceNumber2, 16);
int targetNumber;
try {
targetNumber = Convert::ToInt32(value2, 16);
if (!(isNegative) & (targetNumber & 0x80000000) != 0)
throw gcnew OverflowException();
else
Console::WriteLine("0x{0} converts to {1}.", value2, targetNumber);
}
catch (OverflowException ^e) {
Console::WriteLine("Unable to convert '0x{0}' to an integer.", value2);
}
// The example displays the following output:
// Unable to convert '0x80000000' to an integer.
// Create a hexadecimal value out of range of the Integer type.
long sourceNumber = (long) int.MaxValue + 1;
bool isNegative = Math.Sign(sourceNumber) == -1;
string value = Convert.ToString(sourceNumber, 16);
int targetNumber;
try
{
targetNumber = Convert.ToInt32(value, 16);
if (!(isNegative) & (targetNumber & 0x80000000) != 0)
throw new OverflowException();
else
Console.WriteLine("0x{0} converts to {1}.", value, targetNumber);
}
catch (OverflowException)
{
Console.WriteLine("Unable to convert '0x{0}' to an integer.", value);
}
// Displays the following to the console:
// Unable to convert '0x80000000' to an integer.
' Create a hexadecimal value out of range of the Integer type.
Dim sourceNumber As Long = CLng(Integer.MaxValue) + 1
Dim isNegative As Boolean = (Math.Sign(sourceNumber) = -1)
Dim value As String = Convert.ToString(sourceNumber, 16)
Dim targetNumber As Integer
Try
targetNumber = Convert.ToInt32(value, 16)
If Not isNegative And ((targetNumber And &H80000000) <> 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 an integer.", value)
End Try
' Displays the following to the console:
' Unable to convert '0x80000000' to an integer.
适用于
ToInt32(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 32 位有符号整数。Converts the value of the specified 64-bit unsigned integer to an equivalent 32-bit signed integer.
public:
static int ToInt32(System::UInt64 value);
[System.CLSCompliant(false)]
public static int ToInt32 (ulong value);
[<System.CLSCompliant(false)>]
static member ToInt32 : uint64 -> int
Public Shared Function ToInt32 (value As ULong) As Integer
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 32 位带符号整数。A 32-bit signed integer that is equivalent to value.
- 属性
例外
示例
下面的示例尝试将无符号长整数数组中的每个元素转换为有符号整数。The following example attempts to convert each element in an array of unsigned long integers to a signed integer.
ulong[] numbers = { UInt64.MinValue, 121, 340, UInt64.MaxValue };
int result;
foreach (ulong number in numbers)
{
try {
result = Convert.ToInt32(number);
Console.WriteLine("Converted the {0} value {1} to a {2} value {3}.",
number.GetType().Name, number,
result.GetType().Name, result);
}
catch (OverflowException) {
Console.WriteLine("The {0} value {1} is outside the range of the Int32 type.",
number.GetType().Name, number);
}
}
// The example displays the following output:
// Converted the UInt64 value 0 to a Int32 value 0.
// Converted the UInt64 value 121 to a Int32 value 121.
// Converted the UInt64 value 340 to a Int32 value 340.
// The UInt64 value 18446744073709551615 is outside the range of the Int32 type.
Dim numbers() As ULong = { UInt64.MinValue, 121, 340, UInt64.MaxValue }
Dim result As Integer
For Each number As ULong In numbers
Try
result = Convert.ToInt32(number)
Console.WriteLine("Converted the {0} value {1} to a {2} value {3}.", _
number.GetType().Name, number, _
result.GetType().Name, result)
Catch e As OverflowException
Console.WriteLine("The {0} value {1} is outside the range of the Int32 type.", _
number.GetType().Name, number)
End Try
Next
' The example displays the following output:
' Converted the UInt64 value 0 to a Int32 value 0.
' Converted the UInt64 value 121 to a Int32 value 121.
' Converted the UInt64 value 340 to a Int32 value 340.
' The UInt64 value 18446744073709551615 is outside the range of the Int32 type.
适用于
ToInt32(Object)
将指定对象的值转换为 32 位带符号整数。Converts the value of the specified object to a 32-bit signed integer.
public:
static int ToInt32(System::Object ^ value);
public static int ToInt32 (object value);
public static int ToInt32 (object? value);
static member ToInt32 : obj -> int
Public Shared Function ToInt32 (value As Object) As Integer
参数
- value
- Object
用于实现 IConvertible 接口的对象,或为 null。An object that implements the IConvertible interface, or null.
返回
一个等效于 value 的 32 位带符号整数,如果 value 为 null,则为零。A 32-bit signed integer equivalent to value, or zero if value is null.
例外
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-
不支持该转换。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整数。The following example attempts to convert each element in an object array to an integer.
object[] values = { true, -12, 163, 935, 'x', new DateTime(2009, 5, 12),
"104", "103.0", "-1",
"1.00e2", "One", 1.00e2, 16.3e42};
int result;
foreach (object value in values)
{
try {
result = Convert.ToInt32(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 Int32 type.",
value.GetType().Name, value);
}
catch (FormatException) {
Console.WriteLine("The {0} value {1} is not in a recognizable format.",
value.GetType().Name, value);
}
catch (InvalidCastException) {
Console.WriteLine("No conversion to an Int32 exists for the {0} value {1}.",
value.GetType().Name, value);
}
}
// The example displays the following output:
// Converted the Boolean value True to the Int32 value 1.
// Converted the Int32 value -12 to the Int32 value -12.
// Converted the Int32 value 163 to the Int32 value 163.
// Converted the Int32 value 935 to the Int32 value 935.
// Converted the Char value x to the Int32 value 120.
// No conversion to an Int32 exists for the DateTime value 5/12/2009 12:00:00 AM.
// Converted the String value 104 to the Int32 value 104.
// The String value 103.0 is not in a recognizable format.
// Converted the String value -1 to the Int32 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 Int32 value 100.
// The Double value 1.63E+43 is outside the range of the Int32 type.
Dim values() As Object = { True, -12, 163, 935, "x"c, #5/12/2009#, _
"104", "103.0", "-1", _
"1.00e2", "One", 1.00e2, 16.3e42}
Dim result As Integer
For Each value As Object In values
Try
result = Convert.ToInt32(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 Int32 type.", _
value.GetType().Name, value)
Catch e As FormatException
Console.WriteLine("The {0} value {1} is not in a recognizable format.", _
value.GetType().Name, value)
Catch e As InvalidCastException
Console.WriteLine("No conversion to an Int32 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 Int32 value 1.
' Converted the Int32 value -12 to the Int32 value -12.
' Converted the Int32 value 163 to the Int32 value 163.
' Converted the Int32 value 935 to the Int32 value 935.
' Converted the Char value x to the Int32 value 120.
' No conversion to an Int32 exists for the DateTime value 5/12/2009 12:00:00 AM.
' Converted the String value 104 to the Int32 value 104.
' The String value 103.0 is not in a recognizable format.
' Converted the String value -1 to the Int32 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 Int32 value 100.
' The Double value 1.63E+43 is outside the range of the Int32 type.
注解
如果不 value 为 null ,则此方法包装对的 IConvertible.ToInt32 基础类型的实现的调用 value 。Ifvalue is not null, this method wraps a call to the IConvertible.ToInt32 implementation of the underlying type of value.
适用于
ToInt32(SByte)
重要
此 API 不符合 CLS。
将指定的 8 位带符号整数的值转换为等效的 32 位带符号整数。Converts the value of the specified 8-bit signed integer to the equivalent 32-bit signed integer.
public:
static int ToInt32(System::SByte value);
[System.CLSCompliant(false)]
public static int ToInt32 (sbyte value);
[<System.CLSCompliant(false)>]
static member ToInt32 : sbyte -> int
Public Shared Function ToInt32 (value As SByte) As Integer
参数
- value
- SByte
要转换的 8 位带符号整数。The 8-bit signed integer to convert.
返回
一个与 value 等效的 8 位带符号整数。A 8-bit signed integer that is equivalent to value.
- 属性
示例
下面的示例将具有符号字节的数组中的每个元素转换为整数。The following example converts each element in an array of signed bytes to an integer.
sbyte[] numbers = { SByte.MinValue, -1, 0, 10, SByte.MaxValue };
int result;
foreach (sbyte number in numbers)
{
result = Convert.ToInt32(number);
Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.",
number.GetType().Name, number,
result.GetType().Name, result);
}
// The example displays the following output:
// Converted the SByte value -128 to the Int32 value -128.
// Converted the SByte value -1 to the Int32 value -1.
// Converted the SByte value 0 to the Int32 value 0.
// Converted the SByte value 10 to the Int32 value 10.
// Converted the SByte value 127 to the Int32 value 127.
Dim numbers() As SByte = { SByte.MinValue, -1, 0, 10, SByte.MaxValue }
Dim result As Integer
For Each number As SByte In numbers
result = Convert.ToInt32(number)
Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.", _
number.GetType().Name, number, _
result.GetType().Name, result)
Next
' The example displays the following output:
' Converted the SByte value -128 to the Int32 value -128.
' Converted the SByte value -1 to the Int32 value -1.
' Converted the SByte value 0 to the Int32 value 0.
' Converted the SByte value 10 to the Int32 value 10.
' Converted the SByte value 127 to the Int32 value 127.
适用于
ToInt32(Int64)
将指定的 64 位有符号整数的值转换为等效的 32 位有符号整数。Converts the value of the specified 64-bit signed integer to an equivalent 32-bit signed integer.
public:
static int ToInt32(long value);
public static int ToInt32 (long value);
static member ToInt32 : int64 -> int
Public Shared Function ToInt32 (value As Long) As Integer
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 32 位带符号整数。A 32-bit signed integer that is equivalent to value.
例外
示例
下面的示例尝试将长整数数组中的每个元素转换为整数。The following example attempts to convert each element in an array of long integers to an integer.
long[] numbers = { Int64.MinValue, -1, 0, 121, 340, Int64.MaxValue };
int result;
foreach (long number in numbers)
{
try {
result = Convert.ToInt32(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 Int32 type.",
number.GetType().Name, number);
}
}
// The example displays the following output:
// The Int64 value -9223372036854775808 is outside the range of the Int32 type.
// Converted the Int64 value -1 to the Int32 value -1.
// Converted the Int64 value 0 to the Int32 value 0.
// Converted the Int64 value 121 to the Int32 value 121.
// Converted the Int64 value 340 to the Int32 value 340.
// The Int64 value 9223372036854775807 is outside the range of the Int32 type.
Dim numbers() As Long = { Int64.MinValue, -1, 0, 121, 340, Int64.MaxValue }
Dim result As Integer
For Each number As Long In numbers
Try
result = Convert.ToInt32(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 Int32 type.", _
number.GetType().Name, number)
End Try
Next
' The example displays the following output:
' The Int64 value -9223372036854775808 is outside the range of the Int32 type.
' Converted the Int64 value -1 to the Int32 value -1.
' Converted the Int64 value 0 to the Int32 value 0.
' Converted the Int64 value 121 to the Int32 value 121.
' Converted the Int64 value 340 to the Int32 value 340.
' The Int64 value 9223372036854775807 is outside the range of the Int32 type.
适用于
ToInt32(Int32)
返回指定的 32 位有符号整数;不执行实际的转换。Returns the specified 32-bit signed integer; no actual conversion is performed.
public:
static int ToInt32(int value);
public static int ToInt32 (int value);
static member ToInt32 : int -> int
Public Shared Function ToInt32 (value As Integer) As Integer
参数
- value
- Int32
要转换的 32 位无符号整数。The 32-bit signed integer to return.
返回
不经更改即返回 value。value is returned unchanged.
适用于
ToInt32(Int16)
将指定的 16 位有符号整数的值转换为等效的 32 位有符号整数。Converts the value of the specified 16-bit signed integer to an equivalent 32-bit signed integer.
public:
static int ToInt32(short value);
public static int ToInt32 (short value);
static member ToInt32 : int16 -> int
Public Shared Function ToInt32 (value As Short) As Integer
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 32 位带符号整数。A 32-bit signed integer that is equivalent to value.
示例
下面的示例将16位带符号整数数组中的每个元素转换为整数。The following example converts each element in an array of 16-bit signed integers to an integer.
short[] numbers= { Int16.MinValue, -1, 0, 121, 340, Int16.MaxValue };
int result;
foreach (short number in numbers)
{
result = Convert.ToInt32(number);
Console.WriteLine("Converted the {0} value {1} to a {2} value {3}.",
number.GetType().Name, number,
result.GetType().Name, result);
}
// The example displays the following output:
// Converted the Int16 value -32768 to a Int32 value -32768.
// Converted the Int16 value -1 to a Int32 value -1.
// Converted the Int16 value 0 to a Int32 value 0.
// Converted the Int16 value 121 to a Int32 value 121.
// Converted the Int16 value 340 to a Int32 value 340.
// Converted the Int16 value 32767 to a Int32 value 32767.
Dim numbers() As Short = { Int16.MinValue, -1, 0, 121, 340, Int16.MaxValue }
Dim result As Integer
For Each number As Short In numbers
result = Convert.ToInt32(number)
Console.WriteLine("Converted the {0} value {1} to a {2} value {3}.", _
number.GetType().Name, number, _
result.GetType().Name, result)
Next
' The example displays the following output:
' Converted the Int16 value -32768 to a Int32 value -32768.
' Converted the Int16 value -1 to a Int32 value -1.
' Converted the Int16 value 0 to a Int32 value 0.
' Converted the Int16 value 121 to a Int32 value 121.
' Converted the Int16 value 340 to a Int32 value 340.
' Converted the Int16 value 32767 to a Int32 value 32767.
适用于
ToInt32(Double)
将指定的双精度浮点数的值转换为等效的 32 位带符号整数。Converts the value of the specified double-precision floating-point number to an equivalent 32-bit signed integer.
public:
static int ToInt32(double value);
public static int ToInt32 (double value);
static member ToInt32 : double -> int
Public Shared Function ToInt32 (value As Double) As Integer
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 32 位有符号整数。value, rounded to the nearest 32-bit signed integer. 如果 value 为两个整数中间的数字,则返回二者中的偶数;即 4.5 转换为 4,而 5.5 转换为 6。If value is halfway between two whole numbers, the even number is returned; that is, 4.5 is converted to 4, and 5.5 is converted to 6.
例外
示例
下面的示例尝试将值数组中的每个元素转换 Double 为整数。The following example attempts to convert each element in an array of Double values to an integer.
double[] values= { Double.MinValue, -1.38e10, -1023.299, -12.98,
0, 9.113e-16, 103.919, 17834.191, Double.MaxValue };
int result;
foreach (double value in values)
{
try {
result = Convert.ToInt32(value);
Console.WriteLine("Converted the {0} value '{1}' to the {2} value {3}.",
value.GetType().Name, value,
result.GetType().Name, result);
}
catch (OverflowException) {
Console.WriteLine("{0} is outside the range of the Int32 type.", value);
}
}
// -1.79769313486232E+308 is outside the range of the Int32 type.
// -13800000000 is outside the range of the Int32 type.
// Converted the Double value '-1023.299' to the Int32 value -1023.
// Converted the Double value '-12.98' to the Int32 value -13.
// Converted the Double value '0' to the Int32 value 0.
// Converted the Double value '9.113E-16' to the Int32 value 0.
// Converted the Double value '103.919' to the Int32 value 104.
// Converted the Double value '17834.191' to the Int32 value 17834.
// 1.79769313486232E+308 is outside the range of the Int32 type.
Dim values() As Double = { Double.MinValue, -1.38e10, -1023.299, -12.98, _
0, 9.113e-16, 103.919, 17834.191, Double.MaxValue }
Dim result As Integer
For Each value As Double In values
Try
result = Convert.ToInt32(value)
Console.WriteLine("Converted the {0} value '{1}' to the {2} value {3}.", _
value.GetType().Name, value, _
result.GetType().Name, result)
Catch e As OverflowException
Console.WriteLine("{0} is outside the range of the Int32 type.", value)
End Try
Next
' -1.79769313486232E+308 is outside the range of the Int32 type.
' -13800000000 is outside the range of the Int32 type.
' Converted the Double value '-1023.299' to the Int32 value -1023.
' Converted the Double value '-12.98' to the Int32 value -13.
' Converted the Double value '0' to the Int32 value 0.
' Converted the Double value '9.113E-16' to the Int32 value 0.
' Converted the Double value '103.919' to the Int32 value 104.
' Converted the Double value '17834.191' to the Int32 value 17834.
' 1.79769313486232E+308 is outside the range of the Int32 type.
另请参阅
适用于
ToInt32(Decimal)
将指定的十进制数的值转换为等效的 32 位带符号整数。Converts the value of the specified decimal number to an equivalent 32-bit signed integer.
public:
static int ToInt32(System::Decimal value);
public static int ToInt32 (decimal value);
static member ToInt32 : decimal -> int
Public Shared Function ToInt32 (value As Decimal) As Integer
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 32 位有符号整数。value, rounded to the nearest 32-bit signed integer. 如果 value 为两个整数中间的数字,则返回二者中的偶数;即 4.5 转换为 4,而 5.5 转换为 6。If value is halfway between two whole numbers, the even number is returned; that is, 4.5 is converted to 4, and 5.5 is converted to 6.
例外
示例
下面的示例尝试将值数组中的每个元素转换 Decimal 为整数。The following example attempts to convert each element in an array of Decimal values to an integer.
decimal[] values= { Decimal.MinValue, -1034.23m, -12m, 0m, 147m,
199.55m, 9214.16m, Decimal.MaxValue };
int result;
foreach (decimal value in values)
{
try {
result = Convert.ToInt32(value);
Console.WriteLine("Converted the {0} value '{1}' to the {2} value {3}.",
value.GetType().Name, value,
result.GetType().Name, result);
}
catch (OverflowException) {
Console.WriteLine("{0} is outside the range of the Int32 type.",
value);
}
}
// The example displays the following output:
// -79228162514264337593543950335 is outside the range of the Int32 type.
// Converted the Decimal value '-1034.23' to the Int32 value -1034.
// Converted the Decimal value '-12' to the Int32 value -12.
// Converted the Decimal value '0' to the Int32 value 0.
// Converted the Decimal value '147' to the Int32 value 147.
// Converted the Decimal value '199.55' to the Int32 value 200.
// Converted the Decimal value '9214.16' to the Int32 value 9214.
// 79228162514264337593543950335 is outside the range of the Int32 type.
Dim values() As Decimal = { Decimal.MinValue, -1034.23d, -12d, 0d, 147d, _
199.55d, 9214.16d, Decimal.MaxValue }
Dim result As Integer
For Each value As Decimal In values
Try
result = Convert.ToInt32(value)
Console.WriteLine("Converted the {0} value '{1}' to the {2} value {3}.", _
value.GetType().Name, value, _
result.GetType().Name, result)
Catch e As OverflowException
Console.WriteLine("{0} is outside the range of the Int32 type.", _
value)
End Try
Next
' The example displays the following output:
' -79228162514264337593543950335 is outside the range of the Int32 type.
' Converted the Decimal value '-1034.23' to the Int32 value -1034.
' Converted the Decimal value '-12' to the Int32 value -12.
' Converted the Decimal value '0' to the Int32 value 0.
' Converted the Decimal value '147' to the Int32 value 147.
' Converted the Decimal value '199.55' to the Int32 value 200.
' Converted the Decimal value '9214.16' to the Int32 value 9214.
' 79228162514264337593543950335 is outside the range of the Int32 type.
另请参阅
适用于
ToInt32(DateTime)
调用此方法始终引发 InvalidCastException。Calling this method always throws InvalidCastException.
public:
static int ToInt32(DateTime value);
public static int ToInt32 (DateTime value);
static member ToInt32 : DateTime -> int
Public Shared Function ToInt32 (value As DateTime) As Integer
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.
例外
不支持此转换。This conversion is not supported.
适用于
ToInt32(Char)
将指定的 Unicode 字符的值转换为等效的 32 位有符号整数。Converts the value of the specified Unicode character to the equivalent 32-bit signed integer.
public:
static int ToInt32(char value);
public static int ToInt32 (char value);
static member ToInt32 : char -> int
Public Shared Function ToInt32 (value As Char) As Integer
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 32 位带符号整数。A 32-bit signed integer that is equivalent to value.
示例
下面的示例将值数组中的每个元素转换 Char 为整数。The following example converts each element in an array of Char values to an integer.
char[] chars = { 'a', 'z', '\u0007', '\u03FF',
'\u7FFF', '\uFFFE' };
int result;
foreach (char ch in chars)
{
try {
result = Convert.ToInt32(ch);
Console.WriteLine("Converted the {0} value '{1}' to the {2} value {3}.",
ch.GetType().Name, ch,
result.GetType().Name, result);
}
catch (OverflowException) {
Console.WriteLine("Unable to convert u+{0} to an Int32.",
((int)ch).ToString("X4"));
}
}
// The example displays the following output:
// Converted the Char value 'a' to the Int32 value 97.
// Converted the Char value 'z' to the Int32 value 122.
// Converted the Char value '' to the Int32 value 7.
// Converted the Char value 'Ͽ' to the Int32 value 1023.
// Converted the Char value '翿' to the Int32 value 32767.
// Converted the Char value '' to the Int32 value 65534.
Dim chars() As Char = { "a"c, "z"c, ChrW(7), ChrW(1023), _
ChrW(Short.MaxValue), ChrW(&hFFFE) }
Dim result As Integer
For Each ch As Char in chars
Try
result = Convert.ToInt32(ch)
Console.WriteLine("Converted the {0} value '{1}' to the {2} value {3}.", _
ch.GetType().Name, ch, _
result.GetType().Name, result)
Catch e As OverflowException
Console.WriteLine("Unable to convert u+{0} to an Int32.", _
AscW(ch).ToString("X4"))
End Try
Next
' The example displays the following output:
' Converted the Char value 'a' to the Int32 value 97.
' Converted the Char value 'z' to the Int32 value 122.
' Converted the Char value '' to the Int32 value 7.
' Converted the Char value 'Ͽ' to the Int32 value 1023.
' Converted the Char value '翿' to the Int32 value 32767.
' Converted the Char value '' to the Int32 value 65534.
注解
ToInt32(Char)方法返回一个32位有符号整数,该整数表示自变量的 utf-16 编码的代码单元 value 。The ToInt32(Char) method returns a 32-bit signed integer that represents the UTF-16 encoded code unit of the value argument. 如果不是 value 低代理项或高代理项,则此返回值还表示 Unicode 码位值。If value is not a low surrogate or a high surrogate, this return value also represents the Unicode code point of value.
适用于
ToInt32(Byte)
将指定的 8 位无符号整数的值转换为等效的 32 位有符号整数。Converts the value of the specified 8-bit unsigned integer to the equivalent 32-bit signed integer.
public:
static int ToInt32(System::Byte value);
public static int ToInt32 (byte value);
static member ToInt32 : byte -> int
Public Shared Function ToInt32 (value As Byte) As Integer
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 32 位带符号整数。A 32-bit signed integer that is equivalent to value.
示例
下面的示例将字节数组中的每个元素转换为整数。The following example converts each element in an array of bytes to an integer.
byte[] bytes = { Byte.MinValue, 14, 122, Byte.MaxValue};
int result;
foreach (byte byteValue in bytes)
{
result = Convert.ToInt32(byteValue);
Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.",
byteValue.GetType().Name, byteValue,
result.GetType().Name, result);
}
// The example displays the following output:
// Converted the Byte value 0 to the Int32 value 0.
// Converted the Byte value 14 to the Int32 value 14.
// Converted the Byte value 122 to the Int32 value 122.
// Converted the Byte value 255 to the Int32 value 255.
Dim bytes() As Byte = { Byte.MinValue, 14, 122, Byte.MaxValue}
Dim result As Integer
For Each byteValue As Byte In bytes
result = Convert.ToInt32(byteValue)
Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.", _
byteValue.GetType().Name, byteValue, _
result.GetType().Name, result)
Next
' The example displays the following output:
' Converted the Byte value 0 to the Int32 value 0.
' Converted the Byte value 14 to the Int32 value 14.
' Converted the Byte value 122 to the Int32 value 122.
' Converted the Byte value 255 to the Int32 value 255.
适用于
ToInt32(Boolean)
将指定的布尔值转换为等效的 32 位带符号整数。Converts the specified Boolean value to the equivalent 32-bit signed integer.
public:
static int ToInt32(bool value);
public static int ToInt32 (bool value);
static member ToInt32 : bool -> int
Public Shared Function ToInt32 (value As Boolean) As Integer
参数
- value
- Boolean
要转换的布尔值。The Boolean value to convert.
返回
如果 value 为 true,则为数字 1;否则,为 0。The number 1 if value is true; otherwise, 0.
示例
下面的示例将 Boolean 值 true 和转换 false 为整数。The following example converts the Boolean values true and false to integers.
bool falseFlag = false;
bool trueFlag = true;
Console.WriteLine("{0} converts to {1}.", falseFlag,
Convert.ToInt32(falseFlag));
Console.WriteLine("{0} converts to {1}.", trueFlag,
Convert.ToInt32(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.ToInt32(falseFlag))
Console.WriteLine("{0} converts to {1}.", trueFlag, _
Convert.ToInt32(trueFlag))
' The example displays the following output:
' False converts to 0.
' True converts to 1.