稳扎稳打Silverlight(54) - 4.0通信之对UDP协议的支持: 通过 UdpAnySourceMulticastClient 实现 ASM（Any

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稳扎稳打Silverlight(54) - 4.0通信之对UDP协议的支持: 通过 UdpAnySourceMulticastClient 实现 ASM（Any Source Multicast），即“任意源多播”

作者：webabcd


介绍
Silverlight 4.0 对 UDP 协议的支持：

• UdpAnySourceMulticastClient - 一个发送信息到多播组并从任意源接收多播信息的客户端，即 ASM 客户端

在线DEMO
http://www.cnblogs.com/webabcd/archive/2010/08/09/1795417.html


示例
演示如何通过 UdpAnySourceMulticastClient 实现 ASM
UdpPacketEventArgs.cs
代码 using System;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;

namespace Silverlight40.Communication
{
    public class UdpPacketEventArgs : EventArgs
    {
        // UDP 包的内容
        public string Message { get; set; }
        // UDP 包的来源的 IPEndPoint 
        public IPEndPoint Source { get; set; }

        public UdpPacketEventArgs(byte[] data, IPEndPoint source)
        {
            this.Message = System.Text.Encoding.UTF8.GetString(data, 0, data.Length);
            this.Source = source;
        }
    }
}

UdpAnySourceMulticastChannel.cs 代码 /*
 * 通过 UdpAnySourceMulticastClient 实现 ASM（Any Source Multicast），即“任意源多播”
 * 多播组基于 IGMP（Internet Group Management Protocol），即“Internet组管理协议”
 * 
 * UdpAnySourceMulticastClient - 一个发送信息到多播组并从任意源接收多播信息的客户端，即 ASM 客户端
 *     BeginJoinGroup(), EndJoinGroup() - 加入多播组的异步方法
 *     BeginReceiveFromGroup(), EndReceiveFromGroup() - 从多播组接收信息的异步方法（可以理解为接收多播组内所有成员发送的信息）
 *     BeginSendToGroup(), EndSendToGroup() - 发送信息到多播组的异步方法（可以理解为发送信息到多播组内的全部成员）
 *     ReceiveBufferSize - 接收信息的缓冲区大小
 *     SendBufferSize - 发送信息的缓冲区大小
 *     
 *     BeginSendTo(), EndSendTo() - 发送信息到指定目标的异步方法
 *     BlockSource() - 阻止指定源，以便不再接收该源发来的信息
 *     UnblockSource() - 取消阻止指定源
 *     MulticastLoopback - 发出的信息是否需要传给自己
 * 
 * 本例为一个通过 UdpAnySourceMulticastClient 实现 ASM 客户端的帮助类
 */

using System;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;

using System.Text;
using System.Net.Sockets;

namespace Silverlight40.Communication
{
    public class UdpAnySourceMulticastChannel : IDisposable
    {
        private UdpAnySourceMulticastClient _client;

        // 接收信息的缓冲区
        private byte[] _buffer;
        // 此客户端是否加入了多播组
        private bool _isJoined;

        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="groupAddress">多播组地址</param>
        /// <param name="port">客户端端口</param>
        /// <param name="maxMessageSize">接收信息的缓冲区大小</param>
        public UdpAnySourceMulticastChannel(IPAddress groupAddress, int port, int maxMessageSize)
        {
            _buffer = new byte[maxMessageSize];
            // 实例化 ASM 客户端，需要指定的参数为：多播组地址；客户端端口
            _client = new UdpAnySourceMulticastClient(groupAddress, port);
        }

        // 收到多播信息后触发的事件
        public event EventHandler<UdpPacketEventArgs> Received;
        private void OnReceived(IPEndPoint source, byte[] data)
        {
            var handler = Received;
            if (handler != null)
                handler(this, new UdpPacketEventArgs(data, source));
        }

        // 加入多播组后触发的事件
        public event EventHandler Opening;
        private void OnOpening()
        {
            var handler = Opening;
            if (handler != null)
                handler(this, EventArgs.Empty);
        }

        // 断开多播组后触发的事件
        public event EventHandler Closing;
        private void OnClosing()
        {
            var handler = Closing;
            if (handler != null)
                handler(this, EventArgs.Empty);
        }

        /// <summary>
        /// 加入多播组
        /// </summary>
        public void Open()
        {
            if (!_isJoined)
            {
                _client.BeginJoinGroup(
                    result =>
                    {
                        _client.EndJoinGroup(result);
                        _isJoined = true;
                        Deployment.Current.Dispatcher.BeginInvoke(
                            () =>
                            {
                                OnOpening();
                                Receive();
                            });
                    }, null);
            }
        }

        public void Close()
        {
            _isJoined = false;
            OnClosing();
            Dispose();
        }

        /// <summary>
        /// 发送信息到多播组，即发送信息到多播组内的所有成员
        /// </summary>
        public void Send(string msg)
        {
            if (_isJoined)
            {
                byte[] data = Encoding.UTF8.GetBytes(msg);

                _client.BeginSendToGroup(data, 0, data.Length,
                    result =>
                    {
                        _client.EndSendToGroup(result);
                    }, null);
            }
        }

        /// <summary>
        /// 从多播组接收信息，即接收多播组内所有成员发送的信息
        /// </summary>
        private void Receive()
        {
            if (_isJoined)
            {
                Array.Clear(_buffer, 0, _buffer.Length);

                _client.BeginReceiveFromGroup(_buffer, 0, _buffer.Length,
                    result =>
                    {
                        IPEndPoint source;
                        _client.EndReceiveFromGroup(result, out source);
                        Deployment.Current.Dispatcher.BeginInvoke(
                            () =>
                            {
                                OnReceived(source, _buffer);
                                Receive();
                            });
                    }, null);
            }
        }

        public void Dispose()
        {
            if (_client != null)
                _client.Dispose();
        }
    }
}

UdpAnySourceMulticastClientDemo.xaml 代码 <navigation:Page x:Class="Silverlight40.Communication.UdpAnySourceMulticastClientDemo" 
           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:navigation="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Navigation"
           Title="UdpAnySourceMulticastClientDemo Page">
    <Grid x:Name="LayoutRoot">
        
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="80" />
            <ColumnDefinition Width="*" />
            <ColumnDefinition Width="60" />
        </Grid.ColumnDefinitions>
        <Grid.RowDefinitions>
            <RowDefinition Height="*" />
            <RowDefinition Height="40" />
        </Grid.RowDefinitions>

        <ListBox Name="lstAllMsg" Grid.ColumnSpan="3" Margin="6" />
        <TextBox Name="txtUserName" Grid.Row="1" Grid.Column="0" Margin="6" />
        <TextBox Name="txtSendMsg" Grid.Row="1" Grid.Column="1" TextWrapping="Wrap" Margin="6" KeyDown="txtMsg_KeyDown" />
        <Button Name="btnSend" Grid.Row="1" Grid.Column="2" Margin="6" Content="发送" Click="btnSend_Click" />

    </Grid>
</navigation:Page>

UdpAnySourceMulticastClientDemo.xaml.cs 代码 /*
 * 用于演示 ASM 的客户端
 */

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using System.Windows.Navigation;

namespace Silverlight40.Communication
{
    public partial class UdpAnySourceMulticastClientDemo : Page
    {
        private UdpAnySourceMulticastChannel _channel;

        public UdpAnySourceMulticastClientDemo()
        {
            InitializeComponent();
        }

        protected override void OnNavigatedTo(NavigationEventArgs e)
        {
            txtUserName.Text = "匿名" + new Random().Next(1000, 9999).ToString();

            _channel = new UdpAnySourceMulticastChannel(IPAddress.Parse("224.0.0.1"), 3006, 2048); 
            _channel.Opening += new EventHandler(_channel_Opening);
            _channel.Received += new EventHandler<UdpPacketEventArgs>(_channel_Received);
            _channel.Closing += new EventHandler(_channel_Closing);

            Application.Current.Exit += new EventHandler(Current_Exit);

            _channel.Open();
        }

        void _channel_Opening(object sender, EventArgs e)
        {
            _channel.Send(string.Format("{0}: 进来了 - [{1}]", txtUserName.Text, DateTime.Now.ToString("HH:mm:ss")));
        }

        void _channel_Received(object sender, UdpPacketEventArgs e)
        {
            // 因为已经指定了接收信息的缓冲区大小是 2048 ，所以如果信息不够 2048 个字节的的话，空白处均为“\0”
            string message = string.Format("{0} - 来自：{1}", e.Message.TrimEnd('\0'), e.Source.ToString()); 
            lstAllMsg.Items.Insert(0, message); 
        }

        void _channel_Closing(object sender, EventArgs e)
        {
            _channel.Send(string.Format("{0}: 离开了 - [{1}]", txtUserName.Text, DateTime.Now.ToString("HH:mm:ss")));
        }

        void Current_Exit(object sender, EventArgs e)
        {
            _channel.Dispose();
        }

        private void btnSend_Click(object sender, RoutedEventArgs e)
        {
            SendMsg();
        }

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

        private void SendMsg()
        {
            _channel.Send(string.Format("{0}: {1} - [{2}]", txtUserName.Text, txtSendMsg.Text, DateTime.Now.ToString("HH:mm:ss")));
            txtSendMsg.Text = "";
        }
    }
}


OK
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