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();

        }