SelectSingleNode如何获取xml一个子节点的值?

SelectSingleNode怎么获取xml一个子节点的值??
<REQUEST>
<ROUTE>
<VERSION> 2.0 </VERSION>
<OBJ_RANGE> 01 </OBJ_RANGE>
<RET_FLAG> Y </RET_FLAG>
</ROUTE>  
</REQUEST>                    

strXmlpath   =   "D:/桌面/xml/loginreq.xml ";
xmldoc.Load(strXmlpath);
XmlDocument   xmldoc   =   new   XmlDocument();
XmlNode   nodeXml   =   xmldoc.SelectSingleNode(   "VERSION ");//这里取不到节点,为什么???
strText   =   nodeXml.InnerXml;

请给我看一下!

[解决办法]
XmlDocument xmlDocument = new XmlDocument();
xmlDocument.Load(strXmlpath);
XmlNode node = xmlDocument.SelectSingleNode( "//appSettings ");