public override bool Fallback( char charUnknownHigh, char charUnknownLow, int index ) {
// check input surrogate pair
if ( !char.IsSurrogatePair( charUnknownHigh, charUnknownLow ) ) {
throw XmlConvert.CreateInvalidSurrogatePairException( charUnknownHigh, charUnknownLow );
}
// If we are already in fallback, throw, it's probably at the suspect character in charEntity
if ( charEntityIndex >= 0 ) {
(new EncoderExceptionFallbackBuffer()).Fallback( charUnknownHigh, charUnknownLow, index );
}
if ( parent.CanReplaceAt( index ) ) {
// Create the replacement character entity
charEntity = string.Format( CultureInfo.InvariantCulture, "&#x{0:X};", new object[] { char.ConvertToUtf32( charUnknownHigh, charUnknownLow ) } );
charEntityIndex = 0;
return true;
}
else {
EncoderFallbackBuffer errorFallbackBuffer = ( new EncoderExceptionFallback() ).CreateFallbackBuffer();
errorFallbackBuffer.Fallback( charUnknownHigh, charUnknownLow, index );
return false;
}
}