委托(delegate)的异步调用

 private void ButAbout_Click(object sender, EventArgs e)
        {
            TestInvoke();
        }

        public void TestInvoke()
        {

            System.Func<string, string> convertMethod = UppercaseString;
          
           
            convertMethod.BeginInvoke(name, new AsyncCallback(sendMessageHandleBack), convertMethod);

         
        }
        string name = "Dakota";
        void sendMessageHandleBack(IAsyncResult ar)
        {
            System.Func<string, string> dlgt = (System.Func<string, string>)ar.AsyncState;

            string ret = dlgt.EndInvoke(ar);

          // int ret= dlgt.EndInvoke<string,int>(sendMessageHandleBack);

            NewMethod(ret);


        }

       private delegate void    NewMethodHandle(string ret);
        private void NewMethod(string ret)
        {
            this.BeginInvoke(new NewMethodHandle(NewMethod2), new object[] { ret });
        
        }

        private void NewMethod2(string ret)
        {         
            this.textBox1.Text = ret;
        }

        private static string UppercaseString(string inputString)
        {
            Thread.Sleep(4000);
            return inputString;
        }