Coolite动态添加按钮

Coolite中动态添加按钮，用传统的  btn.Click +=new EventHandler(btn_Click);无法使用，所以使用了下面这个方法：

 for (int i = 1; i <= QuestionCount; i++)
            {

                Coolite.Ext.Web.Button btn = new  Coolite.Ext.Web.Button();
                btn.ID = "btn" + i.ToString();
                btn.Text = i.ToString();
              
             
                string btnText = i.ToString();
                btn.Listeners.Click.Handler = string.Format ( "Coolite.AjaxMethods.btn_Click('{0}');",i.ToString ());

                FormPanel1.Controls.Add(btn);

             
              
            }

 

 [AjaxMethod]
        public void btn_Click(string btnText)
        {
            Ext.Msg.Alert("提示", btnText).Show();
        }