DecoderFallbackBuffer.Fallback(Byte[], Int32) Method


When overridden in a derived class, prepares the fallback buffer to handle the specified input byte sequence.

 abstract bool Fallback(cli::array <System::Byte> ^ bytesUnknown, int index);
public abstract bool Fallback (byte[] bytesUnknown, int index);
abstract member Fallback : byte[] * int -> bool
Public MustOverride Function Fallback (bytesUnknown As Byte(), index As Integer) As Boolean



An input array of bytes.


The index position of a byte in bytesUnknown.


true if the fallback buffer can process bytesUnknown; false if the fallback buffer ignores bytesUnknown.


The Encoding.GetChars, Encoding.GetString, and Decoder.Convert methods call Fallback if they encounter an unknown input byte sequence that cannot be decoded. A return value of true indicates that the fallback buffer can process the input byte sequence, which causes the calling method to call the GetNextChar method to obtain each character of the fallback buffer. If called in an exception fallback handler, the Fallback method throws an exception because it does not process individual bytes.

Notes to Implementers

You can choose to ignore the index parameter if you don't expect any previous fallback to be remaining in the buffer. Otherwise, index is the index position in the bytesUnknown array.

Applies to