将XmlDocument对象转换为XmlNode对象 - C＃？

Question

How do I convert an XmlDocument to a XmlNode in C#? I need to send the entire XmlDocument object to as an input parameter to a .NET web service.

Answer 1

A XmlDocument is a XmlNode, so you can just pass the document object.

Or you could send its DocumentElement, or any Node returned from an XPath query.

XmlDocument doc = null;
XmlNode node = doc;

XmlNode node = doc.DocumentElement;

XmlNode node = doc.SelectSingleNode("/foo/bar");

No casting or converting is needed unless you need to disambiguate XmlNode from XmlDocument for a method with overloads for both parameter types. If this is the case, use either of the cast or as operators.

Answer 2

If you need to refer to it explicitly as an XmlNode use "as":

XmlDocument doc = ...

XmlNode node = doc as XmlNode;

Answer 3

An XmlDocument is derived from XmlNode, but you could also send the XmlDocument.DocumentElement which is an XmlElement but ultimately derived from XmlNode. You might need to check in XmlDocument.DocumentElement == null.