IFormatProvider 接口
提供用于检索控制格式化的对象的机制。
**命名空间:**System
**程序集:**mscorlib（在 mscorlib.dll 中）
语法
声明
<ComVisibleAttribute(True)> _
Public Interface IFormatProvider
用法
Dim instance As IFormatProvider
[ComVisibleAttribute(true)]
public interface IFormatProvider
[ComVisibleAttribute(true)]
public interface class IFormatProvider
/** @attribute ComVisibleAttribute(true) */
public interface IFormatProvider
ComVisibleAttribute(true)
public interface IFormatProvider
备注
公共语言运行库中的一些方法可以在数值和字符串表示形式之间进行相互转换，这些方法采用字符串参数，该参数包含一个或多个称为格式说明符的字符，这些字符指示如何转换数值。如果格式说明符的含义因区域性而异，则格式化对象提供字符串表示形式中所用的实际字符。
类或数值类型实现此接口的 GetFormat 方法，以获得提供格式信息或实现类型的处理的对象。
例如，IFormatProvider 由 NumberFormatInfo 和 DateTimeFormatInfo 实现。NumberFormatInfo 提供用于格式化基本数据类型的数字的区域性特定信息，而 DateTimeFormatInfo 提供用于格式化日期和时间值的区域性特定信息。
示例
下面的代码示例阐释了如何使用一个类来实现 IFormatProvider 接口和 GetFormat 方法。AnyRadix 类支持“Ra”格式设置代码，并将 Int64 值转换为介于 2 到 36 之间的任何指定基数的字符串。如果 Type 参数引用的类实现 ICustomFormatter，则 GetFormat 返回对其自身的引用；否则，GetFormat 返回 空引用（在 Visual Basic 中为 Nothing）。
' Sample for the IFormatProvider interface and
' the IFormatProvider.GetFormat( Type ) method.
Imports System
Imports Microsoft.VisualBasic
' This class implements the "Ra" formatting code. An instance of this
' class should be passed to methods requiring an IFormatProvider.
Public Class AnyRadix
Implements ICustomFormatter
Implements IFormatProvider
' The value to be formatted is returned as a signed string
' of digits from the rDigits array.
Const radixCode As String = "Ra"
Private Shared rDigits As Char( ) = { _
"0"c, "1"c, "2"c, "3"c, "4"c, "5"c, "6"c, "7"c, "8"c, _
"9"c, "A"c, "B"c, "C"c, "D"c, "E"c, "F"c, "G"c, "H"c, _
"I"c, "J"c, "K"c, "L"c, "M"c, "N"c, "O"c, "P"c, "Q"c, _
"R"c, "S"c, "T"c, "U"c, "V"c, "W"c, "X"c, "Y"c, "Z"c }
' This method returns an object that implements ICustomFormatter
' to do the formatting.
Public Function GetFormat( argType As Type ) As Object _
Implements IFormatProvider.GetFormat
' Here, the same object (Me) is returned, but it would be
' possible to return an object of a different type.
If argType Is GetType( ICustomFormatter ) Then
Return Me
Else
Return Nothing
End If
End Function
' This method does the formatting only if it recognizes the
' format codes.
Public Function Format( formatString As String, _
argToBeFormatted As Object, _
provider As IFormatProvider ) As String _
Implements ICustomFormatter.Format
' If no format string is provided or the format string cannot
' be handled, use IFormattable or standard string processing.
If formatString Is Nothing OrElse _
Not formatString.Trim( ).StartsWith( radixCode ) Then
If TypeOf argToBeFormatted Is IFormattable Then
Return CType( argToBeFormatted, IFormattable ). _
ToString( formatString, provider )
Else
Return argToBeFormatted.ToString( )
End If
End If
' The formatting is handled here.
Dim digitIndex As Integer = 0
Dim radix As Long
Dim longToBeFormatted As Long
Dim longPositive As Long
Dim outDigits( 63 ) As Char
' Extract the radix from the format string.
formatString = formatString.Replace( radixCode, "" )
Try
radix = Convert.ToInt64( formatString )
Catch ex As Exception
Throw New ArgumentException( String.Format( _
"The radix ""{0}"" is invalid.", _
formatString ), ex )
End Try
' Verify that the radix is in the proper range.
If radix < 2 OrElse radix > 36 Then
Throw New ArgumentException( String.Format( _
"The radix ""{0}"" is not in the range 2..36.", _
formatString ) )
End If
' Verify that the argument can be converted to a long integer.
Try
longToBeFormatted = CType( argToBeFormatted, Long )
Catch ex As Exception
Throw New ArgumentException( String.Format( _
"The argument ""{0}"" cannot be " & _
"converted to an integer value.", _
argToBeFormatted ), ex )
End Try
' Extract the magnitude for conversion.
longPositive = Math.Abs( longToBeFormatted )
' Convert the magnitude to a digit string.
For digitIndex = 0 To 64
If longPositive = 0 Then Exit For
outDigits( outDigits.Length - digitIndex - 1 ) = _
rDigits( longPositive Mod radix )
longPositive \= radix
Next digitIndex
' Add a minus sign if the argument is negative.
If longToBeFormatted < 0 Then
outDigits( outDigits.Length - digitIndex - 1 ) = "-"c
digitIndex += 1
End If
Return New String( outDigits, _
outDigits.Length - digitIndex, digitIndex )
End Function
End Class
Module IFormatProviderDemo
Sub ConvertToAnyRadix( argToConvert As Object, _
formatStr As String )
Dim provider As New AnyRadix( )
Dim messageStr As String = _
String.Format( "{{0:{0}}}", formatStr )
' Write the first part of the output line.
Console.Write( "{0,18} {1,-6}", _
argToConvert, formatStr )
' Convert the specified argument using the specified format.
Try
Console.WriteLine( String.Format( _
provider, messageStr, argToConvert ) )
Catch ex As Exception
Dim lineEnd As Integer = _
ex.ToString( ).IndexOf( vbLf )
Console.WriteLine( _
ex.ToString( ).Substring( 0, lineEnd ) )
Console.WriteLine( )
End Try
End Sub
Sub Main( )
Dim TwoToThe32 As Long = 4294967296
Dim fifteenNines As Long = 999999999999999
Console.WriteLine( _
"This example of the IFormatProvider interface " & _
vbCrLf & "and the IFormatProvider." & _
"GetFormat( Type ) method " & vbCrLf & _
"generates the following output." & vbCrLf )
Console.WriteLine( "{0,18} Format Result", "Number" )
Console.WriteLine( "{0,18} ------ ------", "------" )
' These are valid conversions.
ConvertToAnyRadix( TwoToThe32, "Ra2" )
ConvertToAnyRadix( TwoToThe32, "Ra5" )
ConvertToAnyRadix( TwoToThe32, "Ra16" )
ConvertToAnyRadix( TwoToThe32, "Ra23" )
ConvertToAnyRadix( TwoToThe32, "Ra36" )
ConvertToAnyRadix( fifteenNines, "Ra2" )
ConvertToAnyRadix( fifteenNines, "Ra3" )
ConvertToAnyRadix( fifteenNines, "Ra8" )
ConvertToAnyRadix( fifteenNines, "Ra11" )
ConvertToAnyRadix( fifteenNines, "Ra16" )
ConvertToAnyRadix( fifteenNines, "Ra23" )
ConvertToAnyRadix( fifteenNines, "Ra36" )
ConvertToAnyRadix( fifteenNines, "E16" )
ConvertToAnyRadix( fifteenNines, "" )
' These are error conditions.
ConvertToAnyRadix( fifteenNines, "Ra37" )
ConvertToAnyRadix( "ABCDEFGHIJKLM", "Ra16" )
End Sub
End Module
' This example of the IFormatProvider interface
' and the IFormatProvider.GetFormat( Type ) method
' generates the following output.
'
' Number Format Result
' ------ ------ ------
' 4294967296 Ra2 100000000000000000000000000000000
' 4294967296 Ra5 32244002423141
' 4294967296 Ra16 100000000
' 4294967296 Ra23 1606K7IC
' 4294967296 Ra36 1Z141Z4
' 999999999999999 Ra2 11100011010111111010100100110001100111111111111111
' 999999999999999 Ra3 11212010201001210101011021212000
' 999999999999999 Ra8 34327724461477777
' 999999999999999 Ra11 26A6A3689065639
' 999999999999999 Ra16 38D7EA4C67FFF
' 999999999999999 Ra23 1134DIFHLMM4
' 999999999999999 Ra36 9UGXNORJLR
' 999999999999999 E16 9.9999999999999900E+014
' 999999999999999 999999999999999
' 999999999999999 Ra37 System.ArgumentException: The radix "37" is not in
' the range 2..36.
'
' ABCDEFGHIJKLM Ra16 System.ArgumentException: The argument "ABCDEFGHIJK
' LM" cannot be converted to an integer value. ---> System.InvalidCastException
' : Cast from string "ABCDEFGHIJKLM" to type 'Long' is not valid. ---> System.F
' ormatException: Input string was not in a correct format.
// Sample for the IFormatProvider interface and
// the IFormatProvider.GetFormat( Type ) method.
using System;
// This class implements the "Ra" formatting code. An instance of this
// class should be passed to methods requiring an IFormatProvider.
public class AnyRadix : ICustomFormatter, IFormatProvider
{
// The value to be formatted is returned as a signed string
// of digits from the rDigits array.
const string radixCode = "Ra";
private static char[] rDigits = {
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',
'U', 'V', 'W', 'X', 'Y', 'Z' };
// This method returns an object that implements ICustomFormatter
// to do the formatting.
public object GetFormat( Type argType )
{
// Here, the same object (this) is returned, but it would
// be possible to return an object of a different type.
if ( argType == typeof( ICustomFormatter ) )
return this;
else
return null;
}
// This method does the formatting only if it recognizes the
// format codes.
public string Format( string formatString,
object argToBeFormatted, IFormatProvider provider )
{
// If no format string is provided or the format string cannot
// be handled, use IFormattable or standard string processing.
if( formatString == null ||
! formatString.Trim( ).StartsWith( radixCode ) )
{
if( argToBeFormatted is IFormattable )
return ( (IFormattable)argToBeFormatted ).
ToString( formatString, provider );
else
return argToBeFormatted.ToString( );
}
// The formatting is handled here.
int digitIndex = 0;
long radix;
long longToBeFormatted;
long longPositive;
char[ ] outDigits = new char[ 63 ];
// Extract the radix from the format string.
formatString = formatString.Replace( radixCode, "" );
try
{
radix = Convert.ToInt64( formatString );
}
catch( Exception ex )
{
throw new ArgumentException( String.Format(
"The radix \"{0}\" is invalid.",
formatString ), ex );
}
// Verify that the radix is in the proper range.
if( radix <2 || radix > 36 )
throw new ArgumentException( String.Format(
"The radix \"{0}\" is not in the range 2..36.",
formatString ) );
// Verify that the argument can be converted to a long integer.
try
{
longToBeFormatted = (long)argToBeFormatted;
}
catch( Exception ex )
{
throw new ArgumentException( String.Format(
"The argument \"{0}\" cannot be " +
"converted to an integer value.",
argToBeFormatted ), ex );
}
// Extract the magnitude for conversion.
longPositive = Math.Abs( longToBeFormatted );
// Convert the magnitude to a digit string.
for( digitIndex = 0; digitIndex <= 64; digitIndex++ )
{
if( longPositive == 0 ) break;
outDigits[ outDigits.Length - digitIndex - 1 ] =
rDigits[ longPositive % radix ];
longPositive /= radix;
}
// Add a minus sign if the argument is negative.
if( longToBeFormatted < 0 )
outDigits[ outDigits.Length - digitIndex++ - 1 ] =
'-';
return new string( outDigits,
outDigits.Length - digitIndex, digitIndex );
}
}
class IFormatProviderDemo
{
static void ConvertToAnyRadix( object argToConvert,
string formatStr )
{
AnyRadix provider = new AnyRadix( );
string messageStr =
String.Format( "{{0:{0}}}", formatStr );
// Write the first part of the output line.
Console.Write( "{0,18} {1,-6}", argToConvert, formatStr );
// Convert the specified argument using the specified format.
try
{
Console.WriteLine( String.Format(
provider, messageStr, argToConvert ) );
}
catch( Exception ex )
{
// Display the exception without the stack trace.
int lineEnd = ex.ToString( ).IndexOf( '\n' );
Console.WriteLine( "{0}\n",
ex.ToString( ).Substring( 0, lineEnd ) );
}
}
static void Main( )
{
long twoToThe32 = 4294967296;
long fifteenNines = 999999999999999;
Console.WriteLine(
"This example of the IFormatProvider interface \n" +
"and the IFormatProvider.GetFormat( Type ) method " +
"\ngenerates the following output.\n" );
Console.WriteLine( "{0,18} Format Result", "Number" );
Console.WriteLine( "{0,18} ------ ------", "------" );
// These are valid conversions.
ConvertToAnyRadix( twoToThe32, "Ra2" );
ConvertToAnyRadix( twoToThe32, "Ra5" );
ConvertToAnyRadix( twoToThe32, "Ra16" );
ConvertToAnyRadix( twoToThe32, "Ra23" );
ConvertToAnyRadix( twoToThe32, "Ra36" );
ConvertToAnyRadix( fifteenNines, "Ra2" );
ConvertToAnyRadix( fifteenNines, "Ra3" );
ConvertToAnyRadix( fifteenNines, "Ra8" );
ConvertToAnyRadix( fifteenNines, "Ra11" );
ConvertToAnyRadix( fifteenNines, "Ra16" );
ConvertToAnyRadix( fifteenNines, "Ra23" );
ConvertToAnyRadix( fifteenNines, "Ra36" );
ConvertToAnyRadix( fifteenNines, "E16" );
ConvertToAnyRadix( fifteenNines, "" );
// These are error conditions.
ConvertToAnyRadix( fifteenNines, "Ra37" );
ConvertToAnyRadix( "ABCDEFGHIJKLM", "Ra16" );
}
}
/*
This example of the IFormatProvider interface
and the IFormatProvider.GetFormat( Type ) method
generates the following output.
Number Format Result
------ ------ ------
4294967296 Ra2 100000000000000000000000000000000
4294967296 Ra5 32244002423141
4294967296 Ra16 100000000
4294967296 Ra23 1606K7IC
4294967296 Ra36 1Z141Z4
999999999999999 Ra2 11100011010111111010100100110001100111111111111111
999999999999999 Ra3 11212010201001210101011021212000
999999999999999 Ra8 34327724461477777
999999999999999 Ra11 26A6A3689065639
999999999999999 Ra16 38D7EA4C67FFF
999999999999999 Ra23 1134DIFHLMM4
999999999999999 Ra36 9UGXNORJLR
999999999999999 E16 9.9999999999999900E+014
999999999999999 999999999999999
999999999999999 Ra37 System.ArgumentException: The radix "37" is not in th
e range 2..36.
ABCDEFGHIJKLM Ra16 System.ArgumentException: The argument "ABCDEFGHIJKLM
" cannot be converted to an integer value. ---> System.InvalidCastException: Sp
ecified cast is not valid.
*/
// Sample for the IFormatProvider interface and
// the IFormatProvider::GetFormat( Type* ) method.
using namespace System;
// This class implements the "Ra" formatting code. An instance of this
// class should be passed to methods requiring an IFormatProvider.
ref class AnyRadix: public IFormatProvider, public ICustomFormatter
{
private:
static Object^ null = nullptr;
// The value to be formatted is returned as a signed string
// of digits from the rDigits array.
static String^ radixCode = "Ra";
static array<Char>^rDigits = {'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'};
public:
// This method returns an object that implements ICustomFormatter
// to do the formatting.
virtual Object^ GetFormat( Type^ argType )
{
// Here, the same object (this) is returned, but it would
// be possible to return an object of a different type.
if ( argType == ICustomFormatter::typeid )
return this;
else
return null;
}
// This method does the formatting only if it recognizes the
// format codes.
virtual String^ Format( String^ formatString, Object^ argToBeFormatted, IFormatProvider^ provider )
{
// If no format string is provided or the format string cannot
// be handled, use IFormattable or standard string processing.
if ( formatString == null || !formatString->Trim()->StartsWith( radixCode ) )
{
if ( dynamic_cast<IFormattable^>(argToBeFormatted) != nullptr )
return static_cast<IFormattable^>(argToBeFormatted)->ToString( formatString, provider );
else
return argToBeFormatted->ToString();
}
// The formatting is handled here.
int digitIndex = 0;
__int64 radix;
__int64 longToBeFormatted;
__int64 longPositive;
array<Char>^outDigits = gcnew array<Char>(64);
// Extract the radix from the format string.
formatString = formatString->Replace( radixCode, "" );
try
{
radix = Convert::ToInt64( formatString );
}
catch ( Exception^ ex )
{
throw gcnew ArgumentException( String::Format( "The radix \"{0}\" is invalid.\n", formatString ),ex );
}
// Verify that the radix is in the proper range.
if ( radix < 2 || radix > 36 )
throw gcnew ArgumentException( String::Format( "The radix \"{0}\" is not in the range 2..36.", formatString ) );
// Verify that the argument can be converted to a long integer.
try
{
longToBeFormatted = *static_cast<__int64^>(argToBeFormatted);
}
catch ( Exception^ ex )
{
throw gcnew ArgumentException( String::Format( "The argument \"{0}\" cannot be "
"converted to an integer value.", argToBeFormatted ),ex );
}
// Extract the magnitude for conversion.
longPositive = Math::Abs( longToBeFormatted );
// Convert the magnitude to a digit string.
for ( digitIndex = 0; longPositive != 0 && digitIndex <= 64; digitIndex++ )
{
outDigits[ outDigits->Length - digitIndex - 1 ] = rDigits[ longPositive % radix ];
longPositive /= radix;
}
// Add a minus sign if the argument is negative.
if ( longToBeFormatted < 0 )
outDigits[ outDigits->Length - digitIndex++ - 1 ] = '-';
return gcnew String( outDigits,outDigits->Length - digitIndex,digitIndex );
}
};
void ConvertToAnyRadix( Object^ argToConvert, String^ formatStr )
{
AnyRadix^ provider = gcnew AnyRadix;
String^ messageStr = String::Format( "{{0:{0}}}", formatStr );
// Write the first part of the output line.
Console::Write( "{0,18} {1,-6}", argToConvert, formatStr );
// Convert the specified argument using the specified format.
try
{
array<Object^>^argArray = {argToConvert};
Console::WriteLine( String::Format( provider, messageStr, argArray ) );
}
catch ( Exception^ ex )
{
// Display the exception without the stack trace.
int lineEnd = ex->ToString()->IndexOf( '\n' );
Console::WriteLine( "{0}\n", ex->ToString()->Substring( 0, lineEnd ) );
}
}
int main()
{
__int64 twoToThe32 = 4294967296;
__int64 fifteenNines = 999999999999999;
Console::WriteLine( "This example of the IFormatProvider interface \n"
"and the IFormatProvider::GetFormat( Type* ) method "
"\ngenerates the following output.\n" );
Console::WriteLine( "{0,18} Format Result", "Number" );
Console::WriteLine( "{0,18} ------ ------", "------" );
// These are valid conversions.
ConvertToAnyRadix( twoToThe32, "Ra2" );
ConvertToAnyRadix( twoToThe32, "Ra5" );
ConvertToAnyRadix( twoToThe32, "Ra16" );
ConvertToAnyRadix( twoToThe32, "Ra23" );
ConvertToAnyRadix( twoToThe32, "Ra36" );
ConvertToAnyRadix( fifteenNines, "Ra2" );
ConvertToAnyRadix( fifteenNines, "Ra3" );
ConvertToAnyRadix( fifteenNines, "Ra8" );
ConvertToAnyRadix( fifteenNines, "Ra11" );
ConvertToAnyRadix( fifteenNines, "Ra16" );
ConvertToAnyRadix( fifteenNines, "Ra23" );
ConvertToAnyRadix( fifteenNines, "Ra36" );
ConvertToAnyRadix( fifteenNines, "E16" );
ConvertToAnyRadix( fifteenNines, "" );
// These are error conditions.
ConvertToAnyRadix( fifteenNines, "Ra37" );
ConvertToAnyRadix( "ABCDEFGHIJKLM", "Ra16" );
}
/*
This example of the IFormatProvider interface
and the IFormatProvider::GetFormat( Type* ) method
generates the following output.
Number Format Result
------ ------ ------
4294967296 Ra2 100000000000000000000000000000000
4294967296 Ra5 32244002423141
4294967296 Ra16 100000000
4294967296 Ra23 1606K7IC
4294967296 Ra36 1Z141Z4
999999999999999 Ra2 11100011010111111010100100110001100111111111111111
999999999999999 Ra3 11212010201001210101011021212000
999999999999999 Ra8 34327724461477777
999999999999999 Ra11 26A6A3689065639
999999999999999 Ra16 38D7EA4C67FFF
999999999999999 Ra23 1134DIFHLMM4
999999999999999 Ra36 9UGXNORJLR
999999999999999 E16 9.9999999999999900E+014
999999999999999 999999999999999
999999999999999 Ra37 System.ArgumentException: The radix "37" is not in th
e range 2..36.
ABCDEFGHIJKLM Ra16 System.ArgumentException: The argument "ABCDEFGHIJKLM
" cannot be converted to an integer value. ---> System.InvalidCastException: Sp
ecified cast is not valid.
*/
// Sample for the IFormatProvider interface and
// the IFormatProvider.GetFormat( Type ) method.
import System.*;
// This class implements the "Ra" formatting code. An instance of this
// class should be passed to methods requiring an IFormatProvider.
public class AnyRadix implements ICustomFormatter,IFormatProvider
{
// The value to be formatted is returned as a signed string
// of digits from the rDigits array.
private String radixCode = "Ra";
private static char rDigits[] = {
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',
'U', 'V', 'W', 'X', 'Y', 'Z' };
// This method returns an object that implements ICustomFormatter
// to do the formatting.
public Object GetFormat(Type argType)
{
// Here, the same object (this) is returned, but it would
// be possible to return an object of a different type.
if ( argType.Equals(ICustomFormatter.class.ToType()) ) {
return this ;
}
else {
return null ;
}
} //GetFormat
// This method does the formatting only if it recognizes the
// format codes.
public String Format(String formatString, Object argToBeFormatted,
IFormatProvider provider)
{
// If no format string is provided or the format string cannot
// be handled, use IFormattable or standard string processing.
if(formatString == null||!(formatString.Trim().StartsWith(radixCode))) {
if ( argToBeFormatted instanceof IFormattable ) {
return((IFormattable)(argToBeFormatted)).
ToString(formatString,provider);
}
else {
return argToBeFormatted.ToString();
}
}
// The formatting is handled here.
int digitIndex = 0;
long radix;
long longToBeFormatted;
long longPositive;
char outDigits[] = new char[63];
// Extract the radix from the format string.
formatString = formatString.Replace(radixCode, "");
try {
radix = Convert.ToInt64(formatString);
}
catch(System.Exception ex) {
throw new ArgumentException(String.Format(
"The radix \"{0}\" is invalid.", formatString), ex);
}
// Verify that the radix is in the proper range.
if ( radix < 2 || radix > 36 ) {
throw new ArgumentException(String.Format(
"The radix \"{0}\" is not in the range 2..36.", formatString));
}
// Verify that the argument can be converted to a long integer.
try {
longToBeFormatted =(long)System.Convert.ToUInt64(argToBeFormatted);
}
catch(System.Exception ex) {
throw new ArgumentException(String.Format(
"The argument \"{0}\" cannot be "
+ "converted to an integer value.", argToBeFormatted), ex);
}
// Extract the magnitude for conversion.
longPositive = System.Math.Abs(longToBeFormatted);
// Convert the magnitude to a digit string.
for(digitIndex = 0;digitIndex <= 64;digitIndex++) {
if ( longPositive == 0 ) {
break ;
}
outDigits[outDigits.length - digitIndex - 1] =
rDigits[(int)(longPositive % radix)];
longPositive /= radix;
}
// Add a minus sign if the argument is negative.
if ( longToBeFormatted < 0 ) {
outDigits [outDigits.length - digitIndex ++ - 1] = '-';
}
return new String(outDigits, outDigits.length - digitIndex, digitIndex);
} //Format
} //AnyRadix
class IFormatProviderDemo
{
static void ConvertToAnyRadix(Object argToConvert, String formatStr)
{
AnyRadix provider = new AnyRadix();
String messageStr = String.Format("{{0:{0}}}", formatStr);
// Write the first part of the output line.
Console.Write("{0,18} {1,-6}", argToConvert, formatStr);
// Convert the specified argument using the specified format.
try {
Console.WriteLine(String.Format((IFormatProvider)provider,
messageStr,new Object[]{ argToConvert}));
}
catch(System.Exception ex) {
// Display the exception without the stack trace.
int lineEnd = ex.ToString().IndexOf('\n');
Console.WriteLine("{0}\n", ex.ToString().Substring(0, lineEnd));
}
} //ConvertToAnyRadix
public static void main(String[] args)
{
long twoToThe32 = 4294967296L;
long fifteenNines = 999999999999999L;
Console.WriteLine(("This example of the IFormatProvider interface \n"
+ "and the IFormatProvider.GetFormat( Type ) method "
+ "\ngenerates the following output.\n"));
Console.WriteLine("{0,18} Format Result", "Number");
Console.WriteLine("{0,18} ------ ------", "------");
// These are valid conversions.
ConvertToAnyRadix(((System.UInt64 )(twoToThe32)), "Ra2");
ConvertToAnyRadix(((System.UInt64)(twoToThe32)), "Ra5");
ConvertToAnyRadix(((System.UInt64)(twoToThe32)), "Ra16");
ConvertToAnyRadix(((System.UInt64)(twoToThe32)), "Ra23");
ConvertToAnyRadix(((System.UInt64)(twoToThe32)), "Ra36");
ConvertToAnyRadix(((System.UInt64)(fifteenNines)), "Ra2");
ConvertToAnyRadix(((System.UInt64)(fifteenNines)), "Ra3");
ConvertToAnyRadix(((System.UInt64)(fifteenNines)), "Ra8");
ConvertToAnyRadix(((System.UInt64)(fifteenNines)), "Ra11");
ConvertToAnyRadix(((System.UInt64)(fifteenNines)), "Ra16");
ConvertToAnyRadix(((System.UInt64)(fifteenNines)), "Ra23");
ConvertToAnyRadix(((System.UInt64)(fifteenNines)), "Ra36");
ConvertToAnyRadix(((System.UInt64)(fifteenNines)), "E16");
ConvertToAnyRadix(((System.UInt64)(fifteenNines)), "");
// These are error conditions.
ConvertToAnyRadix(((System.UInt64)(fifteenNines)), "Ra37");
ConvertToAnyRadix("ABCDEFGHIJKLM", "Ra16");
} //main
} //IFormatProviderDemo
/*
This example of the IFormatProvider interface
and the IFormatProvider.GetFormat( Type ) method
generates the following output.
Number Format Result
------ ------ ------
4294967296 Ra2 100000000000000000000000000000000
4294967296 Ra5 32244002423141
4294967296 Ra16 100000000
4294967296 Ra23 1606K7IC
4294967296 Ra36 1Z141Z4
999999999999999 Ra2 11100011010111111010100100110001100111111111111111
999999999999999 Ra3 11212010201001210101011021212000
999999999999999 Ra8 34327724461477777
999999999999999 Ra11 26A6A3689065639
999999999999999 Ra16 38D7EA4C67FFF
999999999999999 Ra23 1134DIFHLMM4
999999999999999 Ra36 9UGXNORJLR
999999999999999 E16 9.9999999999999900E+014
999999999999999 999999999999999
999999999999999 Ra37 System.ArgumentException: The radix "37" is not in th
e range 2..36.
ABCDEFGHIJKLM Ra16 System.ArgumentException: The argument "ABCDEFGHIJKLM"
cannot be converted to an integer value. ---> System.FormatException: Input str
ing was not in a correct format.
*/
平台
Windows 98、Windows 2000 SP4、Windows CE、Windows Millennium Edition、Windows Mobile for Pocket PC、Windows Mobile for Smartphone、Windows Server 2003、Windows XP Media Center Edition、Windows XP Professional x64 Edition、Windows XP SP2、Windows XP Starter Edition
.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表，请参见系统要求。
版本信息
.NET Framework
受以下版本支持：2.0、1.1、1.0
.NET Compact Framework
受以下版本支持：2.0、1.0
请参见
参考
IFormatProvider 成员
System 命名空间
ICustomFormatter 接口
IFormattable