When overridden in a derived class, retrieves the next character in the fallback buffer.
Assembly: mscorlib (in mscorlib.dll)
A decoding operation calls the Fallback method if the operation encounters an unknown byte sequence in the input. If the Fallback method returns true, a substitute string exists that can be inserted in the output instead of decoding the unknown input. The decoding operation calls the method repeatedly and obtains the substitute string one character at a time. When all characters in the fallback buffer have been returned to the decoder, the method should return U+0000.
For an exception fallback handler, the method should return U+0000.