委托作用：把任务托付于某个方法。

实例：   

　　public delegate void ShowMSG();//定义委托获取线程内返回内容

　　ShowMSG showmsg = new ShowMSG(BindShop);
　　this.Invoke(showmsg);

        //刷新shoptree
        public void BindShop()
        {
            this.shoptreeview.ShopBind();
            eventargs.messageName = "";
            BindComboxCase();
        }