How to compare select node from treeview with xml file

Hi,
I bind xml file to treeview using xslt transformation.
When i select the treeview node,I want to check whether selected node is present xml or not?
I wrote like as
XmlNode xn=TreeView1.SelectedNode; if(xn.Name=="VegaMessage") { }

I got error 
Error    1    Cannot implicitly convert type 'System.Web.UI.WebControls.TreeNode' to 'System.Xml.XmlNode'    E:\SVN_WORK1\Projects\Server\VegaFABSWeb\Admin\DataDictionary.aspx.cs    49    24    E:\...\VegaFABSWeb\


So i changed my code as


TreeNode xnchild = TreeView1.SelectedNode;
        if (xnchild.Text== "VegaMessage")
        {
      &nbs ...