1         public delegate string DgTest(); 2         private void btn_District_Click(object sender, EventArgs e) 3         {   4             //实例化 委托对象 并把方法传入委托 5             DgTest dg = Test; 6             IAsyncResult ir =dg.BeginInvoke(null,null); 7             //接收 返回值 8             string res = dg.EndInvoke(ir); 9         }10 11         string Test()12         {13             //code...14         }