When overridden in a derived class, generates and writes the surrogate character entity for the surrogate character pair.
Type Reason ArgumentException An invalid surrogate character pair was passed. InvalidOperationException The XmlWriter.WriteState is WriteState.Closed.
This method is only applicable on systems that use UTF-16 encoding.
The surrogate character entity is written in hexadecimal format. The range for surrogate characters is #x10000 to #x10FFFF. The following formula is used to generate the surrogate character entity: (highChar -0xD800) * 0x400 + (lowChar -0xDC00) + 0x10000
For both HTML and XML, the document character set (and therefore the notation of numeric character references) is based on UCS [ISO-10646]. A single numeric character reference in a source document may therefore in some cases correspond to two 16-bit units in a string (a high surrogate and a low surrogate). These 16-bit units are referred to as a surrogate pair.
For more information regarding surrogates or characters, refer to section 3.7 of the Unicode 3.0/Unicode 2.0 standard located at http://www.unicode.org, or section 2.2 of the W3C XML 1.0 Recommendation located at http://www.w3.org/TR/REC-xml#charsets.
For the asynchronous version of this method, see XmlWriter.WriteSurrogateCharEntityAsync(char, char).