Silverlight Socket通信学习笔记-51CTO.COM

之前因为项目的关系，涉及到与服务器实时通信，比如通过GPRS将GPS的位置信息等信息发送到服务器，然后再转发给Silverlight应用程序，最后在地图上标示出实时的地理位置，查了查相关的资料，网上给出的比较好的方法就是利用Socket与服务器通信。于是这两天看了看Silverlight下的Socket通信，在此将学习的心得和实现过程作一个记录，以供相互学习和交流。

园子里关于这方面的内容已经有很多大神写过了，这里小小的推荐一下：

http://www.cnblogs.com/webabcd/archive/2008/12/22/1359551.html

因此本文的重点知识说一下具体实现的过程，细节和原理性的东西不会太多，因为本人也是新手，所以就不卖弄了。之前说到和地图结合，所以本文的后续工作将会把Silverlight的Socket通信与ArcGIS 的地图结合，来实现一个小小的功能，而本篇则主要关于Socket的实现过程。下面就进入正题吧。

一.Silverlight的Socket通信和控制台、WinForm下的Socket通信有很大的区别。

对于后两者的Socket通信，其过程就是开启端口，绑定端口，监听端口，连接，接收数据，发送数据。

而在Silverlight中则不太一样，在Silverlight中，首先是Silverlight客户端自动向943端口的服务器端发送一个“<policy-file-request/>”的语句请求，然后服务器端向客户端发送策略文件：

clientaccesspolicy.xml，例如：

<?xml version="1.0" encoding="utf-8" ?> 
<access-policy> 
  <cross-domain-access> 
    <policy> 
      <allow-from> 
        <domain uri="*"/> 
      </allow-from> 
      <grant-to> 
        <socket-resource port="4502-4534" protocol="tcp"/> 
      </grant-to> 
    </policy> 
  </cross-domain-access> 
</access-policy>

发送之后，才允许和服务器进行Socket通信，之后的过程则都是一样。

二、服务器端

2.1、Silverligh中发送策略文件服务

上面说到，Silverlight中，服务器端会向客户端发送策略文件，然后才能开始Socket通信，下面给出服务器端的发送策略文件服务的代码，该代码是在网上找的，是别人已经写好的一个类，所以在编写Silverlight 的Socket通信程序时，只要添加这个类就好了，代码如下：

using System;  
using System.Net.Sockets;  
using System.Net;  
using System.Threading;  
using System.IO;  
using System.Windows.Forms;  
 
namespace WindowsServer  
{  
    class PolicySocketServer  
    {  
        TcpListener _Listener = null;  
        TcpClient _Client = null;  
        static ManualResetEvent _TcpClientConnected = new ManualResetEvent(false);  
        const string _PolicyRequestString = "<policy-file-request/>";  
        int _ReceivedLength = 0;  
        byte[] _Policy = null;  
        byte[] _ReceiveBuffer = null;  
 
        private void InitializeData()  
        {  
            string policyFile = Path.Combine(Application.StartupPath, "clientaccesspolicy.xml");  
            using (FileStream fs = new FileStream(policyFile, FileMode.Open))  
            {  
                _Policy = new byte[fs.Length];  
                fs.Read(_Policy, 0, _Policy.Length);  
            }  
            _ReceiveBuffer = new byte[_PolicyRequestString.Length];  
        }  
        public void StartSocketServer()  
        {  
            InitializeData();  
 
            try  
            {  
                _Listener = new TcpListener(IPAddress.Any, 943);  
                _Listener.Start();  
                while (true)  
                {  
                    _TcpClientConnected.Reset();  
                    _Listener.BeginAcceptTcpClient(new AsyncCallback(OnBeginAccept), null);  
                    _TcpClientConnected.WaitOne();  
                }  
            }  
            catch (Exception)  
            {  
            }  
        }  
 
        private void OnBeginAccept(IAsyncResult ar)  
        {  
            _Client = _Listener.EndAcceptTcpClient(ar);  
            _Client.Client.BeginReceive(_ReceiveBuffer, 0, _PolicyRequestString.Length, SocketFlags.None,  
                new AsyncCallback(OnReceiveComplete), null);  
        }  
 
        private void OnReceiveComplete(IAsyncResult ar)  
        {  
            try  
            {  
                _ReceivedLength += _Client.Client.EndReceive(ar);  
                if (_ReceivedLength < _PolicyRequestString.Length)  
                {  
                    _Client.Client.BeginReceive(_ReceiveBuffer, _ReceivedLength,  
                        _PolicyRequestString.Length - _ReceivedLength,  
                        SocketFlags.None, new AsyncCallback(OnReceiveComplete), null);  
                    return;  
                }  
                string request = System.Text.Encoding.UTF8.GetString(_ReceiveBuffer, 0, _ReceivedLength);  
                if (StringComparer.InvariantCultureIgnoreCase.Compare(request, _PolicyRequestString) != 0)  
                {  
                    _Client.Client.Close();  
                    return;  
                }  
                _Client.Client.BeginSend(_Policy, 0, _Policy.Length, SocketFlags.None,  
                    new AsyncCallback(OnSendComplete), null);  
            }  
            catch (Exception)  
            {  
                _Client.Client.Close();  
            }  
            _ReceivedLength = 0;  
            _TcpClientConnected.Set(); //Allow waiting thread to proceed   
        }  
 
        private void OnSendComplete(IAsyncResult ar)  
        {  
            try  
            {  
                _Client.Client.EndSendFile(ar);  
            }  
            catch (Exception)  
            {  
            }  
            finally  
            {  
                _Client.Client.Close();  
            }  
        }   
    }  
}

2.2、启动策略文件服务，声明Socket，监听端口，接收数据，发送数据。

启动策略文件服务

#region Start The Policy Server 验证策略文件  
            PolicySocketServer StartPolicyServer = new PolicySocketServer();  
            Thread th = new Thread(new ThreadStart(StartPolicyServer.StartSocketServer));  
            th.IsBackground = true;  
            th.Start();  
            #endregion

声明Socket，绑定端口，开始监听

private void StartButton_Click(object sender, EventArgs e)  
        {//创建Socket  
            listener = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);  
            //获取主机信息  
            IPHostEntry ipHostInfo = Dns.GetHostEntry(Dns.GetHostName());  
 
            //把IP和端口转换化为IPEndPoint实例,端口号取4530  
            //Win7 中开启了IPV6的地址，因此0,1对应的是IPV6的地址，2，3对应IPV4地址，3对应本机的IP地址  
            //XP中没有开启IPV6  
            HostIPTextBox.Text = ipHostInfo.AddressList[3].ToString();  
 
            if (!string.IsNullOrEmpty(PortTextBox.Text))  
            {  
                //获取端口号  
                int port = Convert.ToInt32(PortTextBox.Text.Trim());  
                //获得本机的IP地址  
                localEP = new IPEndPoint(ipHostInfo.AddressList[3], port);  
            }  
            else  
            {  
               //默认4530端口  
                ipAddress = IPAddress.Parse("127.0.0.1");  
                localEP = new IPEndPoint(ipHostInfo.AddressList[3], 4530);  
            }  
 
            try  
            {  
                //绑定指定的终结点  
                listener.Bind(localEP);  
                //开始监听  
                listener.Listen(10);  
                //一直循环接收客户端的消息，开启监听端口线程  
                ThreadStart threadwatchStart = new ThreadStart(WatchConnecting);  
                threadWatch = new Thread(threadwatchStart);  
                threadWatch.IsBackground = true;  
                threadWatch.Start();  
            }  
            catch (Exception ex)  
            {  
                MessageBox.Show(ex.Data.ToString());  
            }  
        }

连接端口，接收数据

private void WatchConnecting()  
        {  
            ChangeStatue("等待Silverlight客户端连接.....");  
            while (true)  //持续不断监听客户端发来的请求    
            {  
                listener.BeginAccept(AcceptCallBack, listener);  
                _flipFlop.WaitOne();  
            }  
        }

private  void AcceptCallBack(IAsyncResult asyresult)  
        {  
            Socket listener = (Socket)asyresult.AsyncState;  
            Socket socket = listener.EndAccept(asyresult);  
            ChangeStatue("连接到Silverlight客户端....");  
            _flipFlop.Set();  
            var state = new StateObject();  
            state.Socket = socket;  
            socket.BeginReceive(state.Buffer, 0, StateObject.BufferSize, 0, ReciverCallBack, state);  
        }

private void ReciverCallBack(IAsyncResult asyResult)  
        {  
            StateObject state = (StateObject)asyResult.AsyncState;  
            Socket socket = state.Socket;  
            int read = socket.EndReceive(asyResult);  
            if (read > 0)  
            {  
                string chunk = Encoding.UTF8.GetString(state.Buffer, 0, read);  
                state.StringBuilder.Append(chunk);  
                if (state.StringBuilder.Length > 0)  
                {  
                    string result = state.StringBuilder.ToString();  
                    ChangeStatue("成功接收到消息："+result);  
                    ChangeReciveText(result);  
                    Send(socket, SendTextBox.Text);  
                    AddListItems("接收消息："+result+"\n");  
                    AddListItems("发送消息：" + SendTextBox.Text + "\n");  
                }  
            }  
        }

发送数据

private void Send(Socket handler, String data)  
        {  
            byte[] byteData = Encoding.UTF8.GetBytes(data);  
            handler.BeginSend(byteData, 0, byteData.Length, 0, new AsyncCallback(SendCallBack), handler);  
        }  
 
        private void SendCallBack(IAsyncResult asyResult)  
        {  
            try  
            {  
                Socket handler = (Socket)asyResult.AsyncState;  
                int byteSent = handler.EndSend(asyResult);  
                if (byteSent > 0)  
                {  
                    ChangeStatue("发送数据成功！");  
                }  
            }  
            catch (Exception ex)  
            {  
                MessageBox.Show(ex.Data.ToString());  
            }  
        }

StateObject类：

public class StateObject  
    {  
        public Socket Socket;  
        public StringBuilder StringBuilder = new StringBuilder();  
        public const int BufferSize = 1024;  
        public byte[] Buffer = new byte[BufferSize];  
        public int TotalSize;  
    }

客户端：

和服务器端类似，客户端的操作包括：声明Socket，指定服务器地址和端口，连接到指定的服务器端口，发送数据，接收数据。

下面是具体的实现代码：

声明Socket

private Socket socket;

指定服务器地址和端口，开始连接

private void SendButton_Click(object sender, RoutedEventArgs e)  
        {  
            if(string.IsNullOrEmpty(IPTextBox.Text)||string.IsNullOrEmpty(PortTextBox.Text))  
            {  
                MessageBox.Show ("请输入主机IP地址和端口号！");  
                return;  
            }  
            //ip地址  
            string host=IPTextBox.Text.Trim();  
            //端口号  
            int port=Convert.ToInt32(PortTextBox.Text.Trim());  
            //建立终结点对象  
            DnsEndPoint hostEntry=new DnsEndPoint(host,port);  
            //创建一个Socket对象  
            socket=new Socket(AddressFamily.InterNetwork,SocketType.Stream,ProtocolType.Tcp);  
            //创建Socket异步事件参数  
            SocketAsyncEventArgs socketEventArg=new SocketAsyncEventArgs ();  
            //将消息转化为发送的byte[]格式  
            byte[]buffer=Encoding.UTF8.GetBytes(MessageTextBox.Text);  
            //注册Socket完成事件  
            socketEventArg.Completed+=new EventHandler<SocketAsyncEventArgs>(socketEventArg_Completed);  
            //设置Socket异步事件远程终结点  
            socketEventArg.RemoteEndPoint=hostEntry;  
            //将定义好的Socket对象赋值给Socket异步事件参数的运行实例属性  
            socketEventArg.UserToken = buffer;  
            try  
            {  
                socket.ConnectAsync(socketEventArg);  
            }  
            catch(SocketException ex)  
            {  
                throw new SocketException((int)ex.ErrorCode);  
            }  
        }

向服务器发送数据，并接受服务器回复的消息。

private void socketEventArg_Completed(object sender, SocketAsyncEventArgs e)  
        {  
           //检查是否发送出错  
            if (e.SocketError != SocketError.Success)  
            {  
                if (e.SocketError == SocketError.ConnectionAborted)  
                {  
                    Dispatcher.BeginInvoke(() => MessageBox.Show("连接超时....请重试！"));  
                }  
                else if (e.SocketError == SocketError.ConnectionRefused)  
                {  
                    Dispatcher.BeginInvoke(() => MessageBox.Show("无法连接到服务器端："+e.SocketError));  
                }else  
                {  
                    Dispatcher.BeginInvoke(() => MessageBox.Show("出错了！"+e.SocketError));  
                }  
                return;  
            }  
           //如果连接上，则发送数据  
            if (e.LastOperation == SocketAsyncOperation.Connect)  
            {  
                    byte[] userbytes = (byte[])e.UserToken;  
                    e.SetBuffer(userbytes, 0, userbytes.Length);  
                    socket.SendAsync(e);  
                      
            }//如果已发送数据，则开始接收服务器回复的消息  
            else if (e.LastOperation == SocketAsyncOperation.Send)  
            {  
                Dispatcher.BeginInvoke(() => 
                {  
                    listBox1.Items.Add("客户端在" + DateTime.Now.ToShortTimeString() + "，发送消息：" + MessageTextBox.Text);  
                });  
                byte[] userbytes = new byte[1024];  
                e.SetBuffer(userbytes, 0, userbytes.Length);  
                socket.ReceiveAsync(e);  
            }//接收服务器数据  
            else if (e.LastOperation == SocketAsyncOperation.Receive)  
            {  
                string RecevieStr = Encoding.UTF8.GetString(e.Buffer, 0, e.Buffer.Length).Replace("\0", "");  
                Dispatcher.BeginInvoke(() => 
                {  
                    listBox1.Items.Add("服务器在" + DateTime.Now.ToShortTimeString() + "，回复消息：" + RecevieStr);  
                });  
                socket.Close();  
            }  
        }

xaml代码：

<UserControl 
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
    xmlns:esri="http://schemas.esri.com/arcgis/client/2009" x:Class="SilverlightSocket.MainPage" 
    mc:Ignorable="d" 
    d:DesignHeight="417" d:DesignWidth="530"> 
 
    <Grid x:Name="LayoutRoot" Background="White"> 
        <Grid.ColumnDefinitions> 
            <ColumnDefinition Width="0.868*"/> 
            <ColumnDefinition Width="0.135*"/> 
        </Grid.ColumnDefinitions> 
        <Grid.RowDefinitions> 
            <RowDefinition/> 
        </Grid.RowDefinitions> 
        <esri:Map Background="White" WrapAround="True" Grid.ColumnSpan="2"> 
            <esri:ArcGISTiledMapServiceLayer Url="http://services.arcgisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer"/> 
        </esri:Map> 
        <StackPanel Grid.Column="1" Background="#7F094870"> 
            <StackPanel.Effect> 
                <DropShadowEffect/> 
            </StackPanel.Effect> 
            <TextBlock x:Name="textBlock1" Text="主机IP" Grid.Column="1" Margin="5,5,0,0" Foreground="#FFE7D4E3" FontWeight="Bold" /> 
            <TextBox x:Name="IPTextBox" Text="169.254.57.67" Grid.Column="1" d:LayoutOverrides="Width" Margin="5,5,0,0" HorizontalAlignment="Left"/> 
            <TextBlock x:Name="textBlock2" Text="端口号" Grid.Column="1" Margin="5,5,0,0" Foreground="#FFE7D4E3" FontWeight="Bold" /> 
            <TextBox x:Name="PortTextBox" Width="51" Text="4530" Grid.Column="1" Margin="5,5,0,0" HorizontalAlignment="Left"/> 
            <TextBlock  x:Name="textBlock4" Text="消息记录：" Height="23" Grid.Column="1" Margin="5,5,0,0" Foreground="#FFE7D4E3" FontWeight="Bold" /> 
            <ListBox  x:Name="listBox1" Grid.Column="1" Margin="5,5,0,0" Height="150" /> 
            <TextBlock x:Name="textBlock3" Text="发送信息内容" Height="16" Grid.Column="1" d:LayoutOverrides="Width" Margin="5,5,0,0" Foreground="#FFE7D4E3" FontWeight="Bold" /> 
            <TextBox x:Name="MessageTextBox" Grid.Column="1" Height="50" Margin="5,5,0,0" /> 
            <Button Content="发送" Height="23" x:Name="SendButton" Grid.Column="1" Margin="5,5,0,0" /> 
            <Button Content="清空" Height="23" x:Name="ClearButton" Grid.Column="1" Margin="5,5,0,0" /> 
        </StackPanel> 
    </Grid> 
</UserControl>

最后效果示意图：

服务器端：

Silverlight客户端：

后续工作中将结合地图来实现模拟实时位置的显示功能。。。。

原文链接：http://www.cnblogs.com/potential/archive/2013/01/23/2873035.html