应用SilverLight 2.0 BETA 2的 支持回调的在线聊天室（二）

下面我们来接着做客户端：
1.在Solution中添加SiliverLight Project，命名为ChatClient
这里，我将对应的网站 放在WCF Service中

2.先在ChatClient工程中 添加DLL引用：
System.Runtime.Serialization.dll
System.ServiceModel.dll
System.ServiceModel.PollingDuplex.dll

3.先绘制一个简单界面，修改Page.xaml 如下：

<UserControl x:Class="ChatClient.Page"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    Width="655" Height="420">
    <Grid x:Name="LayoutRoot"
          Background="White"
          ShowGridLines="True">
        <Grid.RowDefinitions>
            <RowDefinition />
            <RowDefinition Height="40" />
        </Grid.RowDefinitions>

        <Grid ShowGridLines="True"
              Grid.Row="0">
            <Grid.ColumnDefinitions>
                <ColumnDefinition />
                <ColumnDefinition Width="150" />
            </Grid.ColumnDefinitions>

            <!--聊天内容-->
            <!--TODO:加入滚动条-->
            <TextBlock x:Name="txt_CharText"
                       Grid.Column="0"
                       Grid.Row="0"
                       VerticalAlignment="Center"
                       HorizontalAlignment="Center" />
            
            <!--用户列表-->
            <!--TODO:加入滚动条 ListView-->
            <TextBlock x:Name="txt_lstChatters"
                       Grid.Column="1"
                       VerticalAlignment="Top"
                       HorizontalAlignment="Center" />
        </Grid>

        <Grid Grid.Row="1"
              ShowGridLines="True">
            <Grid.ColumnDefinitions>
                <ColumnDefinition />
                <ColumnDefinition Width="75" />
                <ColumnDefinition Width="150" />
                <ColumnDefinition Width="75" />
            </Grid.ColumnDefinitions>

            <!--输入对话框-->
            <TextBox x:Name="tb_Message"
                     Grid.Column="0"
                     Margin="5,5,5,5"
                     KeyDown="tb_Message_KeyDown"/>

            <!--发送按钮-->
            <Button x:Name="btn_Say"
                    Grid.Column="1"
                    Width="70"
                    Height="30"
                    HorizontalAlignment="Center"
                    VerticalAlignment="Center"
                    Click="btn_Say_Click">
                <TextBlock HorizontalAlignment="Center"
                           VerticalAlignment="Center">Send</TextBlock></Button>
            
            <!--名字输入对话框-->
            <TextBox x:Name="tb_Name"
                     Grid.Column="2"
                     Margin="5,5,5,5"
                     Text="Guest"
                     KeyDown="tb_Name_KeyDown"/>
            

            <!--Connect按钮-->
            <Button x:Name="btn_Connect"
                    Grid.Column="3"
                    Width="70"
                    Height="30"
                    HorizontalAlignment="Center"
                    VerticalAlignment="Center"
                    Click="btn_Connect_Click">
                <TextBlock HorizontalAlignment="Center"
                           VerticalAlignment="Center">Connect</TextBlock>
            </Button>

        </Grid>
    </Grid>
</UserControl>

为了方便用户输入，在两个TextBox中 加入了KeyDown事件 用来截获"回车"符

4.在相应的 Page.xaml.cs中 添加如下引用：

using System.ServiceModel;
using System.ServiceModel.Channels;
using System.Threading;

5.添加如下代码，创建Channel

        SynchronizationContext uiThread;
        IDuplexSessionChannel m_Channel;

        public void InitChannel()
        {
            // Grab a reference to the UI thread.
            uiThread = SynchronizationContext.Current;

            uiThread.Post(WriteText, "Connecting" + Environment.NewLine);

            // Instantiate the binding and set the time-outs.
            PollingDuplexHttpBinding binding = new PollingDuplexHttpBinding()
            {
                PollTimeout = TimeSpan.FromSeconds(10),
                InactivityTimeout = TimeSpan.FromMinutes(1)
            };

            // Instantiate and open channel factory from binding.
            IChannelFactory<IDuplexSessionChannel> factory =
                binding.BuildChannelFactory<IDuplexSessionChannel>(new BindingParameterCollection());

            IAsyncResult factoryOpenResult =
                factory.BeginOpen(new AsyncCallback(OnOpenCompleteFactory), factory);
            if (factoryOpenResult.CompletedSynchronously)
            {
                CompleteOpenFactory(factoryOpenResult);
            }
        }

这里利用

SynchronizationContext.Current.Post()

异步向页面输送信息

6.加如相应的完成事件

void OnOpenCompleteFactory(IAsyncResult result)
        {
            if (result.CompletedSynchronously)
                return;
            else
                CompleteOpenFactory(result);

        }

        void CompleteOpenFactory(IAsyncResult result)
        {
            IChannelFactory<IDuplexSessionChannel> factory =
                (IChannelFactory<IDuplexSessionChannel>)result.AsyncState;

            factory.EndOpen(result);

            // The factory is now open. Create and open a channel from the channel factory.
            IDuplexSessionChannel channel =
                factory.CreateChannel(new EndpointAddress("http://192.168.0.13:18600/ChatService.svc"));

            IAsyncResult channelOpenResult =
                channel.BeginOpen(new AsyncCallback(OnOpenCompleteChannel), channel);
            if (channelOpenResult.CompletedSynchronously)
            {
                CompleteOpenChannel(channelOpenResult);
            }
        }

        void OnOpenCompleteChannel(IAsyncResult result)
        {
            if (result.CompletedSynchronously)
                return;
            else
                CompleteOpenChannel(result);
        }

        void CompleteOpenChannel(IAsyncResult result)
        {
            IDuplexSessionChannel channel = (IDuplexSessionChannel)result.AsyncState;

            channel.EndOpen(result);

            this.m_Channel = channel;

            // The channel is now open. Send a message.
            Message message = Message.CreateMessage(channel.GetProperty<MessageVersion>(), "Silverlight/IChat/JoinChat", this.tb_Name.Text.ToString());
            IAsyncResult resultChannel = channel.BeginSend(message, new AsyncCallback(OnSend), channel);
            if (resultChannel.CompletedSynchronously)
            {
                CompleteOnSend(resultChannel);
            }

            // Also start the receive loop to listen for callbacks from the service.
            ReceiveLoop(channel);
        }

注意：
(1)这里的

IDuplexSessionChannel channel =
                factory.CreateChannel(new EndpointAddress("http://192.168.0.13:18600/ChatService.svc"));

这个地址应该添入，WCF Service的地址，不要忘记端口号

(2)利用
IDuplexSessionChannel.BeginSend()方法 与服务器通信

7.完成与服务器通信的相应调用

 void OnSend(IAsyncResult result)
        {
            if (result.CompletedSynchronously)
                return;
            else
                CompleteOnSend(result);
        }


        void CompleteOnSend(IAsyncResult result)
        {
            IDuplexSessionChannel channel = (IDuplexSessionChannel)result.AsyncState;

            channel.EndSend(result); 
        }

        void ReceiveLoop(IDuplexSessionChannel channel)
        {
            // Start listening for callbacks.
            IAsyncResult result = channel.BeginReceive(new AsyncCallback(OnReceiveComplete), channel);
            if (result.CompletedSynchronously)
                CompleteReceive(result);
        }

        void OnReceiveComplete(IAsyncResult result)
        {
            if (result.CompletedSynchronously)
                return;
            else
                CompleteReceive(result);
        }

        void CompleteReceive(IAsyncResult result)
        {
            // A callback was received.
            IDuplexSessionChannel channel = (IDuplexSessionChannel)result.AsyncState;

            try
            {
                Message receivedMessage = channel.EndReceive(result);

                if (receivedMessage == null)
                {
                    // Server closed its output session, can close client channel, 
                    // or continue sending messages to start a new session.
                }
                else
                {
                    // Show the service response in the UI.
                    string text = receivedMessage.GetBody<string>();
                    uiThread.Post(WriteText, text + Environment.NewLine);
                    ReceiveLoop(channel);
                }
            }
            catch (CommunicationObjectFaultedException)
            {
                // The channel inactivity time-out was reached.
            }

        }

        private void SendMessage(string text)
        {
            // The channel is now open. Send a message
            Message message = Message.CreateMessage(this.m_Channel.GetProperty<MessageVersion>(), "Silverlight/IChat/SayChat", text);
            IAsyncResult resultChannel = this.m_Channel.BeginSend(message, new AsyncCallback(OnSend), this.m_Channel);
            if (resultChannel.CompletedSynchronously)
            {
                CompleteOnSend(resultChannel);
            }

            // Also start the receive loop to listen for callbacks from the service.
            ReceiveLoop(this.m_Channel);
        }

8.加入前台逻辑处理

        private void btn_Say_Click(object sender, RoutedEventArgs e)
        {
            SendMessage(this.tb_Message.Text.ToString());
            this.tb_Message.Text = "";
        }

        private void btn_Connect_Click(object sender, RoutedEventArgs e)
        {
            InitChannel();
        }

        private void tb_Message_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.Key == Key.Enter)
            {
                SendMessage(this.tb_Message.Text.ToString());
                this.tb_Message.Text = "";
            }
        }

        private void tb_Name_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.Key == Key.Enter)
            {
                InitChannel();
            }
        }

        void WriteText(object text)
        {
            this.txt_CharText.Text += (string)text;
        }

***********************************华丽的分割线**************************************

至此 一个支持回调的SiliverLight 2.0 聊天室 就完成了，从中间可以看出，SiliverLight对WCF的支持还是不够好，
它并不能连接TCP的WCF Service Host 这样，它所支持的所谓CallBack实际上 是SiliverLight内部自己的轮询，
在本质上，似乎还是没有什么重大的突破，只是做的更有效率一点而已，但是SiliverLight所支持的多线程操作，
使其有更好的可发展空间，这一点，也是让大家十分高兴的~毕竟不会象原来那样，因为种种原因，整个浏览器崩掉~

*****************************

应要求 现在补上我的Sulotion  :   Download