When overridden in a derived class, forces the generation of a character entity for the specified Unicode character value.
Assemblies: System.Xml (in System.Xml.dll)
System.Xml.ReaderWriter (in System.Xml.ReaderWriter.dll)
The character is in the surrogate pair character range, 0xd800 - 0xdfff.
An XmlWriter method was called before a previous asynchronous operation finished. In this case, InvalidOperationException is thrown with the message “An asynchronous operation is already in progress.”
This method writes the Unicode character in hexadecimal character entity reference format.
For the asynchronous version of this method, see WriteCharEntityAsync.