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Encoding.GetEncoding Method (Int32, EncoderFallback, DecoderFallback)

Returns the encoding associated with the specified code page identifier. Parameters specify an error handler for characters that cannot be encoded and byte sequences that cannot be decoded.

Namespace: System.Text
Assembly: mscorlib (in mscorlib.dll)

public static Encoding GetEncoding (
	int codepage,
	EncoderFallback encoderFallback,
	DecoderFallback decoderFallback
)
public static Encoding GetEncoding (
	int codepage, 
	EncoderFallback encoderFallback, 
	DecoderFallback decoderFallback
)
public static function GetEncoding (
	codepage : int, 
	encoderFallback : EncoderFallback, 
	decoderFallback : DecoderFallback
) : Encoding
Not applicable.

Parameters

codepage
encoderFallback

A EncoderFallback object that provides an error handling procedure when a character cannot be encoded with the current encoding.

decoderFallback

A DecoderFallback object that provides an error handling procedure when a byte sequence cannot be decoded with the current encoding.

Return Value

The Encoding object associated with the specified code page.

Exception typeCondition

ArgumentOutOfRangeException

codepage is less than zero or greater than 65535.

ArgumentException

codepage is not supported by the underlying platform.

NotSupportedException

codepage is not supported by the underlying platform.

NoteNote:

Some unsupported code pages cause ArgumentException, while others cause NotSupportedException. Therefore, your code must catch all exceptions indicated in the Exceptions section.

The GetEncoding method relies on the underlying platform to support most code pages. However, the .NET Framework natively supports some encodings.

NoteNote:

The ANSI code pages can be different on different computers, or can be changed for a single computer, leading to data corruption. For the most consistent results, applications should use Unicode, such as UTF-8 (code page 65001) or UTF-16, instead of a specific code page.

For a list of code pages, see the Encoding class topic. The application uses the GetEncodings method to get a list of all encodings.

To get the encoding associated with the default ANSI code page in the operating system's regional and language settings, the application can use GetEncoding(0) or the Default property. To determine the default code pages used on the system, the application uses the Windows API function GetSystemDefaultLangID. To determine the current ANSI code page, the application uses the Windows API function GetACP.

Your application should specify a null reference (Nothing in Visual Basic) for the encoderFallback or decoderFallback parameters to obtain the default encoder and decoder fallbacks for the current encoding. The default encoder and decoder fallbacks substitute a close equivalent, which is known as the best fit, for a character that cannot be encoded or a byte sequence that cannot be decoded.

GetEncoding returns a cached instance with default settings. The application should use the constructors of derived classes to get an instance with different settings. For example, the UTF32Encoding class provides a constructor that allows enabling of error detection.

The following code example demonstrates the Encoding.GetEncoding(String,EncoderFallback,DecoderFallback) method.

// This example demonstrates the EncoderReplacementFallback class.

using System;
using System.Text;

class Sample 
{
    public static void Main() 
    {

// Create an encoding, which is equivalent to calling the 
// ASCIIEncoding class constructor. 
// The EncoderReplacementFallback parameter specifies that the
// string, "(unknown)", replace characters that cannot be encoded. 
// A decoder replacement fallback is also specified, but in this 
// code example the decoding operation cannot fail.  

    Encoding ae = Encoding.GetEncoding(
                  "us-ascii",
                  new EncoderReplacementFallback("(unknown)"), 
                  new DecoderReplacementFallback("(error)"));

// The input string consists of the Unicode characters LEFT POINTING 
// DOUBLE ANGLE QUOTATION MARK (U+00AB), 'X' (U+0058), and RIGHT POINTING 
// DOUBLE ANGLE QUOTATION MARK (U+00BB). 
// The encoding can only encode characters in the US-ASCII range of U+0000 
// through U+007F. Consequently, the characters bracketing the 'X' character
// are replaced with the fallback replacement string, "(unknown)".

    string inputString = "\u00abX\u00bb";
    string decodedString;
    string twoNewLines = "\n\n";
    byte[] encodedBytes = new byte[ae.GetByteCount(inputString)];
    int numberOfEncodedBytes = 0;
    int ix = 0;

// --------------------------------------------------------------------------
    Console.Clear();

// Display the name of the encoding.
    Console.WriteLine("The name of the encoding is \"{0}\".\n", ae.WebName);

// Display the input string in text.
    Console.WriteLine("Input string ({0} characters): \"{1}\"", 
                       inputString.Length, inputString);

// Display the input string in hexadecimal.
    Console.Write("Input string in hexadecimal: ");
    foreach (char c in inputString.ToCharArray()) 
        {
        Console.Write("0x{0:X2} ", (int)c);
        }
    Console.Write(twoNewLines);

// --------------------------------------------------------------------------
// Encode the input string. 

    Console.WriteLine("Encode the input string...");
    numberOfEncodedBytes = ae.GetBytes(inputString, 0, inputString.Length, 
                                       encodedBytes, 0);

// Display the encoded bytes.
    Console.WriteLine("Encoded bytes in hexadecimal ({0} bytes):\n", 
                       numberOfEncodedBytes);
    ix = 0;
    foreach (byte b in encodedBytes)
        {
        Console.Write("0x{0:X2} ", (int)b);
        ix++;
        if (0 == ix % 6) Console.WriteLine();
        }
    Console.Write(twoNewLines);

// --------------------------------------------------------------------------
// Decode the encoded bytes, yielding a reconstituted string.

    Console.WriteLine("Decode the encoded bytes...");
    decodedString = ae.GetString(encodedBytes);

// Display the input string and the decoded string for comparison.
    Console.WriteLine("Input string:  \"{0}\"", inputString);
    Console.WriteLine("Decoded string:\"{0}\"", decodedString);
    }
}
/*
This code example produces the following results:

The name of the encoding is "us-ascii".

Input string (3 characters): "X"
Input string in hexadecimal: 0xAB 0x58 0xBB

Encode the input string...
Encoded bytes in hexadecimal (19 bytes):

0x28 0x75 0x6E 0x6B 0x6E 0x6F
0x77 0x6E 0x29 0x58 0x28 0x75
0x6E 0x6B 0x6E 0x6F 0x77 0x6E
0x29

Decode the encoded bytes...
Input string:  "X"
Decoded string:"(unknown)X(unknown)"

*/

Windows 98, Windows Server 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

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0

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