详解Silverlight定时请求WCF服务的代码

本文讲一下Silverlight做定时请求服务器的数据信息及利用WCF的双工通信，通信过程分为两个部分记录。

一 ，需要建立一个WCF的服务端
这里直接在Silverlight的站点中新建了一个WCF服务，代码如下： 

1. //先定义服务契约 
2.  
3. [ServiceContract]  
4.     public interface IChatService  
5.     {  
6.         [OperationContract]  
7.         bool SendMessage(MessageInfo msg);  
8.  
9.         [OperationContract]  
10.         List<MessageInfo> GetMessages(string UserAccount);  
11.     } 
12.  
13. //再定义数据契约 
14.  
15. [DataContract]  
16.     public class MessageInfo  
17.     {  
18.         [DataMember]         
19.         public string ID { set; get; }         
20.         [DataMember]  
21.         public string Title { set; get; }  
22.         [DataMember]  
23.         public string Message { set; get; }  
24.         [DataMember]  
25.         public DateTime SendTime { set; get; }  
26.         [DataMember]  
27.         public DateTime? ReadTime { set; get; }  
28.         [DataMember]  
29.         public string Sender { set; get; }            
30.         [DataMember]  
31.         public string ReceiveUser { set; get; }  
32.         [DataMember]  
33.         public string ReceiveOrgan { set; get; }  
34.         [DataMember]  
35.         public string ReceiveMode { set; get; }  
36.         [DataMember]  
37.         public int State { set; get; }  
38.         [DataMember]  
39.         public int Receipt { set; get; }  
40.         [DataMember]  
41.         public string Source { set; get; }  
42.  
43.     } 
44.  
45. //最后在webconfig中配置好服务 
46.  
47. <system.serviceModel>  
48.         <behaviors>  
49.             <serviceBehaviors>  
50.                 <behavior name="ChatBehavior">  
51.                     <serviceMetadata httpGetEnabled="true" />  
52.                     <serviceDebug includeExceptionDetailInFaults="false" />  
53.                 </behavior>  
54.             </serviceBehaviors>  
55.         </behaviors>  
56.       <services>  
57.         <service behaviorConfiguration="ChatBehavior" name="WebChat.Web.ChatService">  
58.           <endpoint address="" binding="basicHttpBinding" contract="WebChat.Web.IChatService"></endpoint>  
59.         </service>  
60.       </services>  
61.         <serviceHostingEnvironment multipleSiteBindingsEnabled="true" />  
62.     </system.serviceModel> 

到这里呢，一个服务就Host在IIS上了，可以通过浏览服务或服务引用进行验证服务是否正常运行。

二，在Silverlight中向服务器请求数据 

1. public partial class MainPage : UserControl  
2.     {  
3.         Timer timer;  
4.         ChatService.ChatServiceClient proxy;  
5.  
6.         BasicHttpBinding binding;  
7.         EndpointAddress endPoint;  
8.  
9.         public MainPage()  
10.         {  
11.             InitializeComponent();  
12.  
13.             binding = new BasicHttpBinding();  
14.             endPoint = new EndpointAddress("http://localhost:1939/ChatService.svc%22); 
15.  
16.             timer = new Timer(new TimerCallback(GetMessages),this,100,100);  
17.         }  
18.  
19.         #region 定时检测信息  
20.         public void GetMessages(object obj)  
21.         {  
22.             proxy = new ChatService.ChatServiceClient(binding, endPoint);  
23.             proxy.GetMessagesCompleted  = new EventHandler<ChatService.GetMessagesCompletedEventArgs>(GetMessagesComleted);  
24.             proxy.GetMessagesAsync("wengyuli");  
25.         }  
26.  
27.         void GetMessagesComleted(object sender, ChatService.GetMessagesCompletedEventArgs e)  
28.         {  
29.             if(e.Error==null)  
30.             {  
31.                 if (this.listMsgs.Dispatcher.CheckAccess())  
32.                 {  
33.                   this.listMsgs.ItemsSource= e.Result;  
34.                 }  
35.                 else  
36.                 {  
37.                   this.listMsgs.Dispatcher.BeginInvoke(() => { this.listMsgs.ItemsSource = e.Result; });  
38.                 }  
39.             }  
40.         }  
41.         #endregion  
42.  
43.         #region  发送信息  
44.         private void btnSend_Click(object sender, RoutedEventArgs e)  
45.         {  
46.             ChatService.MessageInfo message = new ChatService.MessageInfo();  
47.             message.ID = Guid.NewGuid().ToString();  
48.             message.Receipt = 0;  
49.             message.ReceiveMode = "user";  
50.             message.ReceiveOrgan = "";  
51.             message.ReceiveUser = "xiejianjun";  
52.             message.Message = this.txtMessage.Text;  
53.             message.Sender = "wengyuli";  
54.             message.SendTime = DateTime.Now;  
55.             message.Source = "web";  
56.             message.State = 0;  
57.             message.Title = this.txtMessage.Text;  
58.  
59.             proxy = new ChatService.ChatServiceClient(binding, endPoint);  
60.             proxy.SendMessageCompleted  = new EventHandler<ChatService.SendMessageCompletedEventArgs>(SendMessageComleted);  
61.  
62.             proxy.SendMessageAsync(message);  
63.         }  
64.         void SendMessageComleted(object sender,ChatService.SendMessageCompletedEventArgs e)  
65.         {  
66.             if (e.Error == null)  
67.             {  
68.                 //MessageBox.Show("服务器返回结果："   e.Result);  
69.             }  
70.         }  
71.         #endregion  
72.     } 

前台：

1. <ListBox Height="213" HorizontalAlignment="Left" DisplayMemberPath="Message" ItemsSource="{Binding MessageInfo}" Name="listMsgs" VerticalAlignment="Top" Width="283" ></ListBox> 

编译并运行后得到数据：