Thanks for your reply. My tree view is working fine with ajax support. This is not my problem at present. Actually what is became my headache is how to get the id of the selected node.
protected void SelectedNodeChanged(object sender, EventArgs e)
string id = treeView1.SelectedNode.???
Because without knowing the id I cannot search the table for contents belongs to that node. I cannot use treeView1.SelectedNode.Text becasue there may be more than one nodes with same text. Is there any way to solve it? Please help me.