webservice 异步调用与控件操作

(1)异步调用:

  shPDA.WRServer.Service yq = new shPDA.WRServer.Service();
            string sql = "select count(*) from 水位预警 where 发布时间>'" + System.DateTime.Now.ToShortDateString() +"'";
            yq.Begingetapp(sql,new AsyncCallback(MyHelloWorld),yq);//调用异步方法

//声明异步方法：

 public void MyHelloWorld(IAsyncResult iar)
        {
            int count = 0;
            shPDA.WRServer.Service yq = (shPDA.WRServer.Service)iar.AsyncState;
            DataSet dt = yq.Endgetapp(iar);
            //结束远程调用
            string tmp = dt.Tables[0].Rows[0][0].ToString();
            if (tmp != "")
                count = System.Convert.ToInt32(tmp);
            dt = yq.getapp("select count(*) from 降雨预警 where 发布时间>'" + System.DateTime.Now.ToShortDateString() + "'");
            tmp = dt.Tables[0].Rows[0][0].ToString();
            if (tmp != "")
                count += System.Convert.ToInt32(tmp);

            if (count > 0)
            { SetText( "今天是" + System.DateTime.Now.ToString("yyyy年MM月dd日,今日" + count.ToString() + "处预警提示！")); }
            else
            {
              SetText("今天是" + System.DateTime.Now.ToString("yyyy年MM月dd日,今日无预警提示！")  );

//settext即下边的委托操作
            }

        }

 

（2）控件操作：

      private delegate void SetTextCallback(string text);

        private void SetText(string text)
        {
            // Invokerequired需要比较调用线程ID和创建线程ID
            // 如果它们不相同则返回true
            if (this.alphaLabel2.Invokerequired)
            {
                SetTextCallback d = new SetTextCallback(SetText);
                this.Invoke(d,new object[] { text });
            }
            else
            {

                this.alphaLabel2.Text += text + '/n';            }        }