Ext.Net中AsyncTreeNode动态加载

<%--前台页面--%>
<ext:TreePanel runat="server">
<Root>
<ext:AsyncTreeNode Text="root">
</ext:AsyncTreeNode>
</Root>
<Listeners>
<BeforeLoad Handler="
Ext.Ajax.request({
url:'...',
method:'post',
success:function(response){
var nodes = Ext.decode(response.responseText);
node.loadNodes(nodes);// node指代该BeforeLoad事件的节点
},
failure:function(){
}
});
"/>
</Listeners>
</ext:TreePanel>

// 后台页面
Ext.Net.TreeNodeCollection tnc = new Ext.Net.TreeNodeCollection();
tnc.Add(new Ext.Net.TreeNode(){
Text = "最终节点",
Leaf = true// Left设为True则该节点无法展开
});
tnc.Add(new Ext.Net.TreeNode(){
Text = "普通节点",
Leaf = false
});
return Content(tnc.ToJson());