IFormatProvider.GetFormat メソッド
指定された型の書式指定サービスを提供するオブジェクトを取得します。
Function GetFormat( _
ByVal formatType As Type _) As Object
[C#]
object GetFormat(
TypeformatType);
[C++]
Object* GetFormat(
Type* formatType);
[JScript]
function GetFormat(
formatType : Type) : Object;
パラメータ
- formatType
取得対象となる書式オブジェクトの型を指定するオブジェクト。
戻り値
formatType が現在のインスタンスと同じ型の場合は、現在のインスタンス。それ以外の場合は null 参照 (Visual Basic では Nothing) 。
解説
このメソッドは、オブジェクトの文字列形式を生成または解析するメソッドにおいて、書式オブジェクトを使用するクラスに実装します。ToString メソッドと Parse メソッドは、そのようなメソッドの例です。
詳細については、 CultureInfo.CurrentCulture のトピックを参照してください。
使用例
[Visual Basic, C#, C++] 次のコード例は、 IFormatProvider インターフェイスと GetFormat メソッドを実装したクラスの使用方法を示したものです。AnyRadix クラスは、"Ra" 書式設定コードをサポートし、 Int64 の値を 2 ～ 36 の指定された基数の文字列に変換します。 GetFormat は、Type パラメータが ICustomFormatter を実装したクラスを参照している場合は、自分自身への参照を返します。それ以外の場合、 GetFormat は null 参照 (Visual Basic では Nothing) を返します。
' 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.
[C#]
// 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.
*/
[C++]
// Sample for the IFormatProvider interface and
// the IFormatProvider::GetFormat( Type* ) method.
#using <mscorlib.dll>
using namespace System;
// This class implements the "Ra" formatting code. An instance of this
// class should be passed to methods requiring an IFormatProvider.
__gc class AnyRadix : public IFormatProvider, public ICustomFormatter
{
static Object* null = 0;
// The value to be formatted is returned as a signed string
// of digits from the rDigits array.
static String* radixCode = S"Ra";
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( dynamic_cast<IFormattable*>( argToBeFormatted ) != 0 )
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;
Char outDigits[] = __gc new Char[ 64 ];
// Extract the radix from the format string.
formatString = formatString->Replace( radixCode, "" );
try
{
radix = Convert::ToInt64( formatString );
}
catch( Exception* ex )
{
throw new ArgumentException( String::Format(
S"The radix \"{0}\" is invalid.\n",
formatString ), ex );
}
// Verify that the radix is in the proper range.
if( radix <2 || radix > 36 )
throw new ArgumentException( String::Format(
S"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<__box __int64 *>( argToBeFormatted );
}
catch( Exception* ex )
{
throw new ArgumentException( String::Format(
S"The argument \"{0}\" cannot be "
S"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 new String( outDigits,
outDigits->Length - digitIndex, digitIndex );
}
};
void ConvertToAnyRadix( Object* argToConvert, String* formatStr )
{
AnyRadix* provider = new AnyRadix( );
String* messageStr =
String::Format( S"{{0:{0}}}", formatStr );
// Write the first part of the output line.
Console::Write( S"{0,18} {1,-6}", argToConvert, formatStr );
// Convert the specified argument using the specified format.
try
{
Object* argArray __gc [] = { 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( S"{0}\n",
ex->ToString( )->Substring( 0, lineEnd ) );
}
}
void main( )
{
__int64 twoToThe32 = 4294967296;
__int64 fifteenNines = 999999999999999;
Console::WriteLine(
S"This example of the IFormatProvider interface \n"
S"and the IFormatProvider::GetFormat( Type* ) method "
S"\ngenerates the following output.\n" );
Console::WriteLine( S"{0,18} Format Result", S"Number" );
Console::WriteLine( S"{0,18} ------ ------", S"------" );
// These are valid conversions.
ConvertToAnyRadix( __box( twoToThe32 ), S"Ra2" );
ConvertToAnyRadix( __box( twoToThe32 ), S"Ra5" );
ConvertToAnyRadix( __box( twoToThe32 ), S"Ra16" );
ConvertToAnyRadix( __box( twoToThe32 ), S"Ra23" );
ConvertToAnyRadix( __box( twoToThe32 ), S"Ra36" );
ConvertToAnyRadix( __box( fifteenNines ), S"Ra2" );
ConvertToAnyRadix( __box( fifteenNines ), S"Ra3" );
ConvertToAnyRadix( __box( fifteenNines ), S"Ra8" );
ConvertToAnyRadix( __box( fifteenNines ), S"Ra11" );
ConvertToAnyRadix( __box( fifteenNines ), S"Ra16" );
ConvertToAnyRadix( __box( fifteenNines ), S"Ra23" );
ConvertToAnyRadix( __box( fifteenNines ), S"Ra36" );
ConvertToAnyRadix( __box( fifteenNines ), S"E16" );
ConvertToAnyRadix( __box( fifteenNines ), S"" );
// These are error conditions.
ConvertToAnyRadix( __box( fifteenNines ), S"Ra37" );
ConvertToAnyRadix( S"ABCDEFGHIJKLM", S"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.
*/
[JScript] JScript のサンプルはありません。Visual Basic、C#、および C++ のサンプルを表示するには、このページの左上隅にある言語のフィルタ ボタン .gif)
をクリックします。
必要条件
プラットフォーム: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 ファミリ, .NET Compact Framework - Windows CE .NET, Common Language Infrastructure (CLI) Standard
参照
IFormatProvider インターフェイス | IFormatProvider メンバ | System 名前空間