C#实现udp点对点通信的完整示例

udp

udp和tcp都是传输协议，最大的不同是，tcp通信前需要建立连接，是更可靠的通信协议，而udp是一个无连接的传输协议，可直接发送数据。两种协议不分优劣，各有各的应用场景，实际应用往往会同时使用两种协议。

C#实现

C#代码实现udp通信的步骤比较简单。
假设：A要向B发送消息。
做法：首先，B需要创建UdpClient，监听某端口；然后，A创建UdpClient，向B的监听端口发送消息；最后B接收到消息，处理消息；
示例程序运行如下：

主要源码

接收类

public class UdpReceiver
    {
        public UdpReceiver(int _port)
        {
            port = _port;
        }
        int port;
        public void StartReceiveData(Action<string> receiveData)
        {
            Task.Run(() => { receiveDataAsync(receiveData); });
        }
        private async void receiveDataAsync(Action<string> receiveData)
        {
            UdpClient udpClient = new UdpClient(port);
            while (true)
            {
                var result = await udpClient.ReceiveAsync();
                string message = Encoding.UTF8.GetString(result.Buffer);
                receiveData?.Invoke(message);
            }
        }
    }

发送类

public class UdpSender
    {
        public UdpSender(string remoteIp, int port)
        {
            remoteEndPoint = new IPEndPoint(IPAddress.Parse(remoteIp), port);
        }
        IPEndPoint remoteEndPoint = null;
        public void Send(string message)
        {
            UdpClient udpClient = new UdpClient();
            byte[] data = Encoding.UTF8.GetBytes(message);
            udpClient.Send(data, data.Length, remoteEndPoint);
            udpClient.Close();
        }
    }

监听命令

public DelegateCommand StartListen
        {
            get
            {
                return new DelegateCommand((port) => 
                {
                    int p = 0;
                    if (!Int32.TryParse(port.ToString(), out p) || p<=1024)
                    {
                        MessageInfos.Add(new MessageInfo() { From = "系统消息", Message = "本机端口输入有误！" });
                        return;
                    }
                    try
                    {
                        StartEnabled = false;
                        UdpReceiver receiver = new UdpReceiver(p);
                        receiver.StartReceiveData((msg) =>
                        {
                            MessageInfos.Add(new MessageInfo() { From = msg.Split(',')[0], Message = msg.Split(',')[1] });
                        });
                        MessageInfos.Add(new MessageInfo() { From = "系统消息", Message = "正在监听端口："+p.ToString() });
                    }
                    catch (Exception e)
                    {
                        MessageInfos.Add(new MessageInfo() { From = "系统消息", Message = "错误：" + e.Message });
                        startEnabled = true;
                    }
                });
            }
        }

发送命令

public DelegateCommand Send
        {
            get
            {
                return new DelegateCommand((msg) => 
                {
                    if (string.IsNullOrEmpty(RemoteIp) || RemotePort <= 0)
                    {
                        MessageInfos.Add(new MessageInfo() { From = "系统消息", Message = "对方IP及端口输入有误！"});
                        return;
                    }
                    UdpSender sender = new UdpSender(RemoteIp, RemotePort);
                    try
                    {
                        sender.Send(LocalIp + ":" + LocalPort.ToString()+","+msg.ToString());
                        MessageInfos.Add(new MessageInfo() { From = LocalIp + ":" + LocalPort.ToString(), Message = msg.ToString() });
                    }
                    catch (Exception e)
                    {
                        MessageInfos.Add(new MessageInfo() { From = "系统消息", Message = "错误：" + e.Message });
                    }
                });
            }
        }

UI绑定

<Window x:Class="UdpDemo.MainWindow"
        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:local="clr-namespace:UdpDemo"
        mc:Ignorable="d"
        Title="Udp点对点通信示例" Height="360" Width="600">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="50"/>
            <RowDefinition Height="50"/>
            <RowDefinition />
        </Grid.RowDefinitions>
        <StackPanel Orientation="Horizontal" VerticalAlignment="Bottom" Margin="20,5">
            <TextBlock Text="本机IP"/>
            <TextBox Text="{Binding LocalIp}" Width="120" Margin="5,0" IsReadOnly="True" />
            <TextBlock Text="本机端口" Margin="5,0"/>
            <TextBox x:Name="txt_Port" Text="{Binding LocalPort}" Width="60" Margin="5,0" IsReadOnly="{Binding Listening}" />
            <Button Width="80" Content="开始监听" Command="{Binding StartListen}" CommandParameter="{Binding ElementName=txt_Port,Path=Text}" IsEnabled="{Binding StartEnabled}" Margin="5,0" />
        </StackPanel>
        <StackPanel Grid.Row="1" Orientation="Horizontal" VerticalAlignment="Bottom" Margin="20,5">
            <TextBlock Text="对方IP"/>
            <TextBox Text="{Binding RemoteIp}" Width="120" Margin="5,0" />
            <TextBlock Text="对方端口" Margin="5,0"/>
            <TextBox Text="{Binding RemotePort}" Width="60" Margin="5,0" />
            <Button Width="80" Content="发送消息" Command="{Binding Send}" CommandParameter="{Binding ElementName=txt_msg,Path=Text}" Margin="5,0" />
            <TextBox x:Name="txt_msg" Width="160" Text="这是一个测试消息！"/>
        </StackPanel>
        <ListView Grid.Row="2" ItemsSource="{Binding MessageInfos}" Margin="5">
            <ListView.ItemTemplate>
                <DataTemplate>
                    <StackPanel Margin="0,2">
                        <TextBlock Text="{Binding From}" Foreground="Gray"/>
                        <TextBlock Text="{Binding Message}" Foreground="Black"/>
                    </StackPanel>
                </DataTemplate>
            </ListView.ItemTemplate>
        </ListView>
    </Grid>
</Window>

完整源码分享

完整源码下载：下载源码
（备注：使用vs2022打开）