Редагувати

Поділитися через

Encoding.GetEncoding Method

  • Reference

Definition

Namespace:
System.Text
Assembly:
System.Text.Encoding.dll
Assembly:
System.Runtime.dll
Assembly:
mscorlib.dll
Assembly:
netstandard.dll

Returns an encoding for the specified code page.

Overloads

GetEncoding(Int32)

Returns the encoding associated with the specified code page identifier.
GetEncoding(String)

Returns the encoding associated with the specified code page name.
GetEncoding(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.
GetEncoding(String, EncoderFallback, DecoderFallback)

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

GetEncoding(Int32)

Source:
Encoding.cs
Source:
Encoding.cs
Source:
Encoding.cs

Returns the encoding associated with the specified code page identifier.

public:
 static System::Text::Encoding ^ GetEncoding(int codepage);
public static System.Text.Encoding GetEncoding (int codepage);
static member GetEncoding : int -> System.Text.Encoding
Public Shared Function GetEncoding (codepage As Integer) As Encoding

Parameters

codepage
Int32

The code page identifier of the preferred encoding. For a list of possible values, see Encoding.

-or-

0 (zero), to use the default encoding.

Returns

Encoding

The encoding that is associated with the specified code page.

Exceptions

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.

Examples

The following example gets two instances of the same encoding (one by code page and another by name), and checks their equality.

using namespace System;
using namespace System::Text;
int main()
{
   
   // Get a UTF-32 encoding by codepage.
   Encoding^ e1 = Encoding::GetEncoding( 12000 );
   
   // Get a UTF-32 encoding by name.
   Encoding^ e2 = Encoding::GetEncoding( "utf-32" );
   
   // Check their equality.
   Console::WriteLine( "e1 equals e2? {0}", e1->Equals( e2 ) );
}

/* 
This code produces the following output.

e1 equals e2? True

*/

using System;
using System.Text;

public class SamplesEncoding  {

   public static void Main()  {

      // Get a UTF-32 encoding by codepage.
      Encoding e1 = Encoding.GetEncoding( 12000 );

      // Get a UTF-32 encoding by name.
      Encoding e2 = Encoding.GetEncoding( "utf-32" );

      // Check their equality.
      Console.WriteLine( "e1 equals e2? {0}", e1.Equals( e2 ) );
   }
}


/* 
This code produces the following output.

e1 equals e2? True

*/

Imports System.Text

Public Class SamplesEncoding   

   Public Shared Sub Main()

      ' Get a UTF-32 encoding by codepage.
      Dim e1 As Encoding = Encoding.GetEncoding(12000)

      ' Get a UTF-32 encoding by name.
      Dim e2 As Encoding = Encoding.GetEncoding("utf-32")

      ' Check their equality.
      Console.WriteLine("e1 equals e2? {0}", e1.Equals(e2))

   End Sub

End Class


'This code produces the following output.
'
'e1 equals e2? True

Remarks

The fallback handler depends on the encoding type of codepage. If codepage is a code page or double-byte character set (DBCS) encoding, a best-fit fallback handler is used. Otherwise, a replacement fallback handler is used. These fallback handlers may not be appropriate for your app. To specify the fallback handler used by the encoding specified by codepage, you can call the GetEncoding(Int32, EncoderFallback, DecoderFallback) overload.

In .NET Framework, the GetEncoding method relies on the underlying platform to support most code pages. However, .NET Framework natively supports some encodings. For a list of code pages, see List of encodings. In .NET Core, the GetEncoding method returns the encodings natively supported by .NET Core. On both .NET implementations, you can call the GetEncodings method to get an array of EncodingInfo objects that contains information about all available encodings.

In addition to the encodings that are natively available on .NET Core or that are intrinsically supported on a specific platform version of .NET Framework, the GetEncoding method returns any additional encodings that are made available by registering an EncodingProvider object. If the same encoding has been registered by multiple EncodingProvider objects, this method returns the last one registered.

You can also supply a value of 0 for the codepage argument. Its precise behavior depends on whether any encodings have been made available by registering an EncodingProvider object:

  • If one or more encoding providers have been registered, it returns the encoding of the last registered provider that has chosen to return a encoding when the GetEncoding method is passed a codepage argument of 0.

  • On .NET Framework, if no encoding provider has been registered, if the CodePagesEncodingProvider is the registered encoding provider, or if no registered encoding provider handles a codepage value of 0, it returns the operating system's active code page. To determine the active code page on Windows systems, call the Windows GetACP function from .NET Framework.

  • On .NET Core, if no encoding provider has been registered or if no registered encoding provider handles a codepage value of 0, it returns the UTF8Encoding.

Note

  • Some unsupported code pages cause an ArgumentException to be thrown, whereas others cause a NotSupportedException. Therefore, your code must catch all exceptions indicated in the Exceptions section.
  • In .NET 5 and later versions, the code page identifier 65000, which represents UTF-7, is not supported.

Note

The ANSI code pages can be different on different computers and can change on a single computer, leading to data corruption. For this reason, if the active code page is an ANSI code page, encoding and decoding data using the default code page returned by Encoding.GetEncoding(0) is not recommended. For the most consistent results, you should use a Unicode encoding, such as UTF-8 (code page 65001) or UTF-16, instead of a specific code page.

GetEncoding returns a cached instance with default settings. You should use the constructors of derived classes to get an instance with different settings. For example, the UTF32Encoding class provides a constructor that lets you enable error detection.

See also

Applies to

GetEncoding(String)

Source:
Encoding.cs
Source:
Encoding.cs
Source:
Encoding.cs

Returns the encoding associated with the specified code page name.

public:
 static System::Text::Encoding ^ GetEncoding(System::String ^ name);
public static System.Text.Encoding GetEncoding (string name);
static member GetEncoding : string -> System.Text.Encoding
Public Shared Function GetEncoding (name As String) As Encoding

Parameters

name
String

The code page name of the preferred encoding. Any value returned by the WebName property is valid. For a list of possible values, see Encoding.

Returns

Encoding

The encoding associated with the specified code page.

Exceptions

ArgumentException

name is not a valid code page name.

-or-

The code page indicated by name is not supported by the underlying platform.

Examples

The following example gets two instances of the same encoding (one by code page and another by name), and checks their equality.

using namespace System;
using namespace System::Text;
int main()
{
   
   // Get a UTF-32 encoding by codepage.
   Encoding^ e1 = Encoding::GetEncoding( 12000 );
   
   // Get a UTF-32 encoding by name.
   Encoding^ e2 = Encoding::GetEncoding( "utf-32" );
   
   // Check their equality.
   Console::WriteLine( "e1 equals e2? {0}", e1->Equals( e2 ) );
}

/* 
This code produces the following output.

e1 equals e2? True

*/

using System;
using System.Text;

public class SamplesEncoding  {

   public static void Main()  {

      // Get a UTF-32 encoding by codepage.
      Encoding e1 = Encoding.GetEncoding( 12000 );

      // Get a UTF-32 encoding by name.
      Encoding e2 = Encoding.GetEncoding( "utf-32" );

      // Check their equality.
      Console.WriteLine( "e1 equals e2? {0}", e1.Equals( e2 ) );
   }
}


/* 
This code produces the following output.

e1 equals e2? True

*/

Imports System.Text

Public Class SamplesEncoding   

   Public Shared Sub Main()

      ' Get a UTF-32 encoding by codepage.
      Dim e1 As Encoding = Encoding.GetEncoding(12000)

      ' Get a UTF-32 encoding by name.
      Dim e2 As Encoding = Encoding.GetEncoding("utf-32")

      ' Check their equality.
      Console.WriteLine("e1 equals e2? {0}", e1.Equals(e2))

   End Sub

End Class


'This code produces the following output.
'
'e1 equals e2? True

Remarks

The fallback handler depends on the encoding type of name. If name is a code page or double-byte character set (DBCS) encoding, a best-fit fallback handler is used. Otherwise, a replacement fallback handler is used. These fallback handlers may not be appropriate for your app. To specify the fallback handler used by the encoding specified by name, you can call the GetEncoding(String, EncoderFallback, DecoderFallback) overload.

In .NET Framework, the GetEncoding method relies on the underlying platform to support most code pages. However, .NET Framework natively supports some encodings. For a list of code pages, see List of encodings. In .NET Core, the GetEncoding method returns the encodings natively supported by .NET Core. On both .NET implementations, you can call the GetEncodings method to get an array of EncodingInfo objects that contains information about all available encodings.

In addition to the encodings that are natively available on .NET Core or that are intrinsically supported on a specific platform version of .NET Framework, the GetEncoding method returns any additional encodings that are made available by registering an EncodingProvider object. If the same encoding has been registered by multiple EncodingProvider objects, this method returns the last one registered.

In .NET 5 and later versions, the code page name utf-7 is not supported.

Note

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

GetEncoding returns a cached instance with default settings. You should use the constructors of derived classes to get an instance with different settings. For example, the UTF32Encoding class provides a constructor that lets you enable error detection.

See also

Applies to

GetEncoding(Int32, EncoderFallback, DecoderFallback)

Source:
Encoding.cs
Source:
Encoding.cs
Source:
Encoding.cs

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.

public:
 static System::Text::Encoding ^ GetEncoding(int codepage, System::Text::EncoderFallback ^ encoderFallback, System::Text::DecoderFallback ^ decoderFallback);
public static System.Text.Encoding GetEncoding (int codepage, System.Text.EncoderFallback encoderFallback, System.Text.DecoderFallback decoderFallback);
static member GetEncoding : int * System.Text.EncoderFallback * System.Text.DecoderFallback -> System.Text.Encoding
Public Shared Function GetEncoding (codepage As Integer, encoderFallback As EncoderFallback, decoderFallback As DecoderFallback) As Encoding

Parameters

codepage
Int32

The code page identifier of the preferred encoding. For a list of possible values, see Encoding.

-or-

0 (zero), to use the default encoding.

encoderFallback
EncoderFallback

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

decoderFallback
DecoderFallback

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

Returns

Encoding

The encoding that is associated with the specified code page.

Exceptions

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.

Examples

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

// This example demonstrates the EncoderReplacementFallback class.

using namespace System;
using namespace System::Text;

int 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^ ascii = Encoding::GetEncoding("us-ascii",
        gcnew EncoderReplacementFallback("(unknown)"),
        gcnew 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 = Environment::NewLine + Environment::NewLine;
    array <Byte>^ encodedBytes = 
        gcnew array<Byte>(ascii->GetByteCount(inputString));
    int numberOfEncodedBytes = 0;

    // ---------------------------------------------------------------------
        // Display the name of the encoding.
    Console::WriteLine("The name of the encoding is \"{0}\".{1}", 
        ascii->WebName, Environment::NewLine);

    // 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: ");
    for each (char c in inputString)
    {
        Console::Write("0x{0:X2} ", c);
    }
    Console::Write(twoNewLines);

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

    Console::WriteLine("Encode the input string...");
    numberOfEncodedBytes = ascii->GetBytes(inputString, 0, inputString->Length,
        encodedBytes, 0);

    // Display the encoded bytes.
    Console::WriteLine("Encoded bytes in hexadecimal ({0} bytes):{1}",
        numberOfEncodedBytes, Environment::NewLine);
    for(int i = 0; i < encodedBytes->Length; i++)
    {
        Console::Write("0x{0:X2} ", encodedBytes[i]);
        if(((i + 1) % 6) == 0)
        {
            Console::WriteLine();
        }
    }
    Console::Write(twoNewLines);

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

    Console::WriteLine("Decode the encoded bytes...");
    decodedString = ascii->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)"

*/

// 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;

// --------------------------------------------------------------------------
// 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)"

*/

' This example demonstrates the EncoderReplacementFallback class.
Imports System.Text

Class Sample
    Public Shared Sub 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.  

        Dim erf As New EncoderReplacementFallback("(unknown)")
        Dim drf As New DecoderReplacementFallback("(error)")
        Dim ae As Encoding = Encoding.GetEncoding("us-ascii", erf, drf)
        
        ' 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)".

        Dim inputString As String = "«X»"
        Dim decodedString As String
        Dim twoNewLines As String = vbCrLf & vbCrLf
        Dim ix As Integer = 0
        Dim numberOfEncodedBytes As Integer = ae.GetByteCount(inputString)
        ' Counteract the compiler adding an extra byte to the array.
        Dim encodedBytes(numberOfEncodedBytes - 1) As Byte
        
        ' --------------------------------------------------------------------------
        ' Display the name of the encoding.
        Console.WriteLine("The name of the encoding is ""{0}""." & vbCrLf, ae.WebName)
        
        ' Display the input string in text.
        Console.WriteLine("Input string ({0} characters): ""{1}""", _
                           inputString.Length, inputString)
        
        ' Display the input string in hexadecimal. 
        ' Each element is converted to an integer with Convert.ToInt32.
        Console.Write("Input string in hexadecimal: ")
        Dim c As Char
        For Each c In inputString.ToCharArray()
            Console.Write("0x{0:X2} ", Convert.ToInt32(c))
        Next 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. 
        ' Each element is converted to an integer with Convert.ToInt32.
        Console.WriteLine("Encoded bytes in hexadecimal ({0} bytes):" & vbCrLf, _
                           numberOfEncodedBytes)
        ix = 0
        Dim b As Byte
        For Each b In encodedBytes
            Console.Write("0x{0:X2} ", Convert.ToInt32(b))
            ix += 1
            If 0 = ix Mod 6 Then
                Console.WriteLine()
            End If
        Next b
        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)
    
    End Sub
End Class
'
'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)"
'

Remarks

Note

  • Some unsupported code pages cause the exception ArgumentException to be thrown, whereas others cause NotSupportedException. Therefore, your code must catch all exceptions indicated in the Exceptions section.
  • In .NET 5 and later versions, the code page identifier 65000, which represents UTF-7, is not supported.

In .NET Framework, the GetEncoding method relies on the underlying platform to support most code pages. However, .NET Framework natively supports some encodings. For a list of code pages, see List of encodings. In .NET Core, the GetEncoding method returns the encodings natively supported by .NET Core. On both .NET implementations, you can call the GetEncodings method to get an array of EncodingInfo objects that contains information about all available encodings.

In addition to the encodings that are natively available on .NET Core or that are intrinsically supported on a specific platform version of .NET Framework, the GetEncoding method returns any additional encodings that are made available by registering an EncodingProvider object. If the same encoding has been registered by multiple EncodingProvider objects, this method returns the last one registered.

You can also supply a value of 0 for the codepage argument. Its precise behavior depends on whether any encodings have been made available by registering an EncodingProvider object:

  • If one or more encoding providers have been registered, it returns the encoding of the last registered provider that has chosen to return a encoding when the GetEncoding method is passed a codepage argument of 0.

  • On .NET Framework, if no encoding provider has been registered, if the CodePagesEncodingProvider is the registered encoding provider, or if no registered encoding provider handles a codepage value of 0, it returns the active code page.

  • On .NET Core, if no encoding provider has been registered or if no registered encoding provider handles a codepage value of 0, it returns the UTF8Encoding encoding.

Note

The ANSI code pages can be different on different computers and can change on a single computer, leading to data corruption. For this reason, if the active code page is an ANSI code page, encoding and decoding data using the default code page returned by Encoding.GetEncoding(0) is not recommended. For the most consistent results, you should use Unicode, such as UTF-8 (code page 65001) or UTF-16, instead of a specific code page.

To get the encoding associated with the active code page, you can either supply a value of 0 for the codepage argument or, if your code is running on .NET Framework, retrieve the value of the Encoding.Default property. To determine the current active code page, call the Windows GetACP function from .NET Framework.

GetEncoding returns a cached instance with default settings. You should use the constructors of derived classes to get an instance with different settings. For example, the UTF32Encoding class provides a constructor that lets you enable error detection.

See also

Applies to

GetEncoding(String, EncoderFallback, DecoderFallback)

Source:
Encoding.cs
Source:
Encoding.cs
Source:
Encoding.cs

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

public:
 static System::Text::Encoding ^ GetEncoding(System::String ^ name, System::Text::EncoderFallback ^ encoderFallback, System::Text::DecoderFallback ^ decoderFallback);
public static System.Text.Encoding GetEncoding (string name, System.Text.EncoderFallback encoderFallback, System.Text.DecoderFallback decoderFallback);
static member GetEncoding : string * System.Text.EncoderFallback * System.Text.DecoderFallback -> System.Text.Encoding
Public Shared Function GetEncoding (name As String, encoderFallback As EncoderFallback, decoderFallback As DecoderFallback) As Encoding

Parameters

name
String

The code page name of the preferred encoding. Any value returned by the WebName property is valid. Possible values are listed in the Name column of the table that appears in the Encoding class topic.

encoderFallback
EncoderFallback

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

decoderFallback
DecoderFallback

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

Returns

Encoding

The encoding that is associated with the specified code page.

Exceptions

ArgumentException

name is not a valid code page name.

-or-

The code page indicated by name is not supported by the underlying platform.

Examples

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

// This example demonstrates the EncoderReplacementFallback class.

using namespace System;
using namespace System::Text;

int 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^ ascii = Encoding::GetEncoding("us-ascii",
        gcnew EncoderReplacementFallback("(unknown)"),
        gcnew 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 = Environment::NewLine + Environment::NewLine;
    array <Byte>^ encodedBytes = 
        gcnew array<Byte>(ascii->GetByteCount(inputString));
    int numberOfEncodedBytes = 0;

    // ---------------------------------------------------------------------
        // Display the name of the encoding.
    Console::WriteLine("The name of the encoding is \"{0}\".{1}", 
        ascii->WebName, Environment::NewLine);

    // 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: ");
    for each (char c in inputString)
    {
        Console::Write("0x{0:X2} ", c);
    }
    Console::Write(twoNewLines);

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

    Console::WriteLine("Encode the input string...");
    numberOfEncodedBytes = ascii->GetBytes(inputString, 0, inputString->Length,
        encodedBytes, 0);

    // Display the encoded bytes.
    Console::WriteLine("Encoded bytes in hexadecimal ({0} bytes):{1}",
        numberOfEncodedBytes, Environment::NewLine);
    for(int i = 0; i < encodedBytes->Length; i++)
    {
        Console::Write("0x{0:X2} ", encodedBytes[i]);
        if(((i + 1) % 6) == 0)
        {
            Console::WriteLine();
        }
    }
    Console::Write(twoNewLines);

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

    Console::WriteLine("Decode the encoded bytes...");
    decodedString = ascii->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)"

*/

// 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;

// --------------------------------------------------------------------------
// 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)"

*/

' This example demonstrates the EncoderReplacementFallback class.
Imports System.Text

Class Sample
    Public Shared Sub 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.  

        Dim erf As New EncoderReplacementFallback("(unknown)")
        Dim drf As New DecoderReplacementFallback("(error)")
        Dim ae As Encoding = Encoding.GetEncoding("us-ascii", erf, drf)
        
        ' 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)".

        Dim inputString As String = "«X»"
        Dim decodedString As String
        Dim twoNewLines As String = vbCrLf & vbCrLf
        Dim ix As Integer = 0
        Dim numberOfEncodedBytes As Integer = ae.GetByteCount(inputString)
        ' Counteract the compiler adding an extra byte to the array.
        Dim encodedBytes(numberOfEncodedBytes - 1) As Byte
        
        ' --------------------------------------------------------------------------
        ' Display the name of the encoding.
        Console.WriteLine("The name of the encoding is ""{0}""." & vbCrLf, ae.WebName)
        
        ' Display the input string in text.
        Console.WriteLine("Input string ({0} characters): ""{1}""", _
                           inputString.Length, inputString)
        
        ' Display the input string in hexadecimal. 
        ' Each element is converted to an integer with Convert.ToInt32.
        Console.Write("Input string in hexadecimal: ")
        Dim c As Char
        For Each c In inputString.ToCharArray()
            Console.Write("0x{0:X2} ", Convert.ToInt32(c))
        Next 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. 
        ' Each element is converted to an integer with Convert.ToInt32.
        Console.WriteLine("Encoded bytes in hexadecimal ({0} bytes):" & vbCrLf, _
                           numberOfEncodedBytes)
        ix = 0
        Dim b As Byte
        For Each b In encodedBytes
            Console.Write("0x{0:X2} ", Convert.ToInt32(b))
            ix += 1
            If 0 = ix Mod 6 Then
                Console.WriteLine()
            End If
        Next b
        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)
    
    End Sub
End Class
'
'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)"
'

Remarks

In .NET Framework, the GetEncoding method relies on the underlying platform to support most code pages. However, .NET Framework natively supports some encodings. For a list of code pages, see List of encodings. In .NET Core, the GetEncoding method returns the encodings natively supported by .NET Core. On both .NET implementations, you can call the GetEncodings method to get an array of EncodingInfo objects that contains information about all available encodings.

In addition to the encodings that are natively available on .NET Core or that are intrinsically supported on a specific platform version of .NET Framework, the GetEncoding method returns any additional encodings that are made available by registering an EncodingProvider object. If the same encoding has been registered by multiple EncodingProvider objects, this method returns the last one registered.

In .NET 5 and later versions, the code page name utf-7 is not supported.

Note

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

GetEncoding returns a cached instance with default settings. You should use the constructors of derived classes to get an instance with different settings. For example, the UTF32Encoding class provides a constructor that lets you enable error detection.

See also

Applies to