In Code behind you can nicely hook an event on TreePanel
like this
 Ext.Net.TreePanel tr = new Ext.Net.TreePanel();
 tr.DirectEvents.Click.Event += nodeClicked;
however if lets say node has attributes how we pass it on extra params ???
  Ext.Net.Parameter prm = new Ext.Net.Parameter();
  prm.Value ="{#{" + tr.ID + "}.node.attributes.tagName}"; //this does not work. Any ideas????
  prm.Name = "ReportID";
  tr.DirectEvents.Click.ExtraParams.Add(prm);