问题
I'm loading valid XHTML into an XmlDocument, but it takes 2 seconds to load. I've found that if I drop the DTD, it's instant, but then I have to replace to  , etc. The number of declared HTML entities is large, so I feel the DTD should be loaded. So what is the easiest way to pre-load the DTD with minimal manual labor? Perhaps if I could, say, put the DTD into the assembly as a resource file and inject it in..? Any suggestions?
回答1:
I found a technique here, by implementing the abstract class XmlResolver and setting it to the XmlDocument's XmlResolver property. The abstract class implementation returns a MemoryStream object for the URL being requested, which contains the DTD or whatever other resource would normally be loaded over HTTP.
http://www.codeproject.com/KB/XML/HTML2XHTML.aspx?display=Print
来源：https://stackoverflow.com/questions/913214/system-xml-xmldocument-whats-the-best-way-to-cache-an-external-dependency-dtd