异步调用webservice

通常的调用webservice方法，在webservice执行期间客户端会一直等待服务执行完毕才能相应，直接影响用户体验。

在webservice中定义一个方法，比如Test(),当调用这webservice时候，会发现不仅有Test()方法，还有一个TestAsync（）。

 public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            MyService.WebService service = new WindowsApplication1.MyService.WebService();
            service.GetNewsAsync(10);
            service.GetNewsCompleted += new WindowsApplication1.MyService.GetNewsCompletedEventHandler(service_GetNewsCompleted);
            ChangeProcess();
        }

        void service_GetNewsCompleted(object sender, WindowsApplication1.MyService.GetNewsCompletedEventArgs e)
        {
            if (e.Error != null)
            {
                throw e.Error;
            }
            progressBar1.Value = progressBar1.Maximum;
            DataSet ds = e.Result;
            if (ds == null || ds.Tables.Count <= 0 || ds.Tables[0].Rows.Count <= 0)
            {
                return;
            }
            for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
            {
                this.listBox1.Items.Add("title:"+ds.Tables[0].Rows[i]["title"].ToString());
                this.listBox1.Items.Add("summary:" + ds.Tables[0].Rows[i]["summary"].ToString());
            }
        }
        void ChangeProcess()
        {
            for (int i = 0; i < 10; i++)
            {
                this.progressBar1.Value = i;
                //System.Threading.Thread.Sleep(5000);
            }
        }
    }