Assembly: mscorlib (in mscorlib.dll)
An encoding maps a Unicode character to an encoded sequence of bytes, which can subsequently be transferred either to a physical medium, such as a disk, or over a communications link. Characters can be mapped in various ways, and a particular encoding is represented by a type derived from the Encoding class. Specifically, the encoding type's GetBytes method encodes a character to a byte sequence, and the GetChars method decodes a byte sequence to a character.
However, an encoding operation can fail if the input character cannot be represented by the encoding. For example, an ASCIIEncoding object cannot encode a character whose Unicode code point value is outside the range U+0000 to U+007F.
In cases where an encoding or decoding conversion cannot be performed, the .NET Framework provides a failure-handling mechanism called a fallback. Your code can use predefined .NET Framework encoder and decoder fallbacks, or you can create a custom encoder fallback derived from the EncoderFallback and EncoderFallbackBuffer classes, or a custom decoder fallback derived from the DecoderFallback and DecoderFallbackBuffer classes.
The .NET Framework provides two classes that implement different fallback strategies for handling encoding conversion failures. The EncoderReplacementFallback class substitutes a string that you provide for any input character that cannot be converted. The substitute string is encoded in place of the invalid character, and then the encoding operation continues converting the remainder of the input. In contrast, the EncoderExceptionFallback class throws an EncoderFallbackException when an invalid character is encountered.
Windows 98, Windows 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.