1、前言

上篇完成了winform版的mqtt服务器和客户端，实现了订阅和发布，效果666，长这样

 这节要做的wpf版，长这样，效果也是帅BBBB帅，wpf技术是cs程序软件的福音。

 wpf的基础知识和案例项目可以看我的另一个专栏系列文章，这里直接干搞，开发环境依然是vs2022，.netframework 4.8，mqttnet3.x。

WPF真入门教程

2、服务器搭建

1、创建项目方案

 2、添加包组件MQTTNET 

3、创建相关的目录及文件 

 

样式文件CommonStyle.xaml

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <Style x:Key="ButtonStyle" TargetType="Button">
        <Setter Property="Background" Value="#3F85FF"></Setter>
        <Setter Property="Foreground" Value="White"></Setter>
        <Setter Property="FocusVisualStyle" Value="{x:Null}"></Setter>
        <Setter Property="Margin" Value="5"></Setter>
        <Setter Property="FontSize" Value="16"></Setter>
        <!--模板的样式-->
        <Setter Property="Template">
            <Setter.Value>
                <!--Button单选按钮样式-->
                <ControlTemplate TargetType="Button">
                    <Grid >
                        <Border Background="{TemplateBinding Background}" CornerRadius="5" >
                            <TextBlock Margin="10 5 10 5" Text="{TemplateBinding Content}" FontSize="{TemplateBinding FontSize}" HorizontalAlignment="Center" VerticalAlignment="Center"></TextBlock>
                        </Border>
                    </Grid>
                    <ControlTemplate.Triggers>
                        <!--鼠标放上去时的触发器-->
                        <Trigger Property="IsMouseOver" Value="True">
                            <Setter Property="Background" Value="DarkOliveGreen" ></Setter>
                        </Trigger>
                    </ControlTemplate.Triggers> 
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</ResourceDictionary>

4、设置UI布局界面 

 

<Window x:Class="MQTTNETServerWPF.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:MQTTNETServerWPF.ViewModel"
        mc:Ignorable="d" Background="Transparent" WindowStartupLocation="CenterScreen"
        FontSize="13" FontFamily="Microsoft YaHei" FontWeight="ExtraLight" Foreground="#333"
        Title="MainWindow" Height="550" Width="890">
    <WindowChrome.WindowChrome>
        <WindowChrome GlassFrameThickness="-1"/>
    </WindowChrome.WindowChrome>
    <Window.DataContext>
        <local:MainWindowViewModel/>
    </Window.DataContext>
    <Grid ShowGridLines="true"  >
        <Grid.RowDefinitions>
            <RowDefinition Height="70"/>
            <RowDefinition/>
        </Grid.RowDefinitions>
        <TextBlock Grid.Row="0" FontWeight="Bold" Background="BlanchedAlmond"  Text="WPF版MQTT服务器程序" FontSize="25" VerticalAlignment="Center" Margin="6,20,0,0" Foreground="#666"   />
        <Grid Grid.Row="1">
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="220"/>
                <ColumnDefinition/>
            </Grid.ColumnDefinitions>
            <Border BorderBrush="#EEE" BorderThickness="0,0,1,0"/>

            <!--左侧布局-->
            <StackPanel Grid.Column="0" Margin="20" >
                <TextBlock Text="主机地址"/>
                <TextBox Text="{Binding Server.ServerIP}" Height="30" VerticalContentAlignment="Center" Padding="5,0" Margin="0,10"  />
                <TextBlock Text="端口号" Margin="0,10,0,0"/>
                <TextBox Text="{Binding Server.ServerPort}" Height="30" VerticalContentAlignment="Center" Padding="5,0" Margin="0,10"  />
                <TextBlock Text="连接账号" Margin="0,10,0,0"/>
                <TextBox Text="{Binding Server.ServerName}"  Height="30" VerticalContentAlignment="Center" Padding="5,0" Margin="0,10"    />
                <TextBlock Text="连接密码" Margin="0,10,0,0"/>
                <TextBox Text="{Binding Server.ServerPwd}" Height="30" VerticalContentAlignment="Center" Padding="5,0" Margin="0,10"  />
                <Button Content="启动服务" Margin="0,30,0,0" Height="30"  Command="{Binding StartCommand}" Style="{StaticResource ButtonStyle}" />
                <Button Content="停止服务" Margin="0,10" Height="30"  Command="{Binding StopCommand}"  Style="{StaticResource ButtonStyle}"/>
            </StackPanel>

            <!--右侧布局-->
            <Grid Grid.Column="1">
                <Grid.RowDefinitions>
                    <RowDefinition Height="2*"/>
                    <RowDefinition Height="3*"/>
                </Grid.RowDefinitions>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition/>
                    <ColumnDefinition/>
                </Grid.ColumnDefinitions>
                <GridSplitter VerticalAlignment="Bottom" HorizontalAlignment="Stretch" Height="4" Background="#F7F9FA" Grid.ColumnSpan="2" Margin="0,0,3,0"/>

                <Grid Margin="20,20,10,15">
                    <Grid.RowDefinitions>
                        <RowDefinition Height="30"/>
                        <RowDefinition/>
                    </Grid.RowDefinitions>
                    <TextBlock Text="在线Client列表"/>
                    <ListBox Grid.Row="1"   ItemsSource="{Binding ClientsList}"/>
                </Grid>

                <Grid Margin="10,20,20,15" Grid.Column="1">
                    <Grid.RowDefinitions>
                        <RowDefinition Height="30"/>
                        <RowDefinition/>
                    </Grid.RowDefinitions>
                    <TextBlock Text="Topic主题列表"/>
                    <ListView Grid.Row="1"   ItemsSource="{Binding TopicsList}">
                    </ListView>
                </Grid>

                <Grid Grid.Row="1" Grid.ColumnSpan="2" Margin="20,10,20,20">
                    <Grid.RowDefinitions>
                        <RowDefinition Height="30"/>
                        <RowDefinition/>
                    </Grid.RowDefinitions>
                    <TextBlock Text="消息"/>
                    <TextBox  Grid.Row="1"   x:Name="txtRich" ToolTip="右键清理内容" Text="{Binding ConnectWords}" Height="200" Background="White" VerticalContentAlignment="Top" Padding="3,0" Margin="10,9,10,10"    >
                        <!--添加一个右键菜单的功能，即清空-->
                        <TextBox.ContextMenu>
                            <ContextMenu>
                                <MenuItem x:Name="menuClear" Click="miClear_Click"  Header="清空内容"></MenuItem>
                            </ContextMenu>
                        </TextBox.ContextMenu>
                    </TextBox>
                </Grid>
            </Grid>
        </Grid>
    </Grid>
</Window>

5、视图模型，属性绑定和命令绑定

完整代码：

using MQTTnet.Client.Receiving;
using MQTTnet;
using MQTTnet.Server;
using MQTTNETServerWPF.Command;
using MQTTNETServerWPF.Model;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Input;
using System.Collections.ObjectModel;
using MQTTnet.Certificates;
using MQTTnet.Protocol;
using System.Runtime.Remoting.Messaging;

namespace MQTTNETServerWPF.ViewModel
{
    public class MainWindowViewModel : ViewModelBase
    {
       
        private IMqttServer mqttserver;//mqtt服务器
        List<TopicItem> Topics = new List<TopicItem>();

        public MainWindowViewModel()
        {
            //创建服务器对象
            mqttserver = new MqttFactory().CreateMqttServer();
            mqttserver.ApplicationMessageReceivedHandler =
                new MqttApplicationMessageReceivedHandlerDelegate(new Action<MqttApplicationMessageReceivedEventArgs>(Server_ApplicationMessageReceived));//绑定消息接收事件
            mqttserver.ClientConnectedHandler =
                new MqttServerClientConnectedHandlerDelegate(new Action<MqttServerClientConnectedEventArgs>(Server_ClientConnected));//绑定客户端连接事件
            mqttserver.ClientDisconnectedHandler = new MqttServerClientDisconnectedHandlerDelegate(new Action<MqttServerClientDisconnectedEventArgs>(Server_ClientDisconnected));//绑定客户端断开事件
            mqttserver.ClientSubscribedTopicHandler = new MqttServerClientSubscribedHandlerDelegate(new Action<MqttServerClientSubscribedTopicEventArgs>(Server_ClientSubscribedTopic));//绑定客户端订阅主题事件
            mqttserver.ClientUnsubscribedTopicHandler = new MqttServerClientUnsubscribedTopicHandlerDelegate(new Action<MqttServerClientUnsubscribedTopicEventArgs>(Server_ClientUnsubscribedTopic));//绑定客户端退订主题事件
            mqttserver.StartedHandler = new MqttServerStartedHandlerDelegate(new Action<EventArgs>(Server_Started));//绑定服务端启动事件
            mqttserver.StoppedHandler = new MqttServerStoppedHandlerDelegate(new Action<EventArgs>(Server_Stopped));//绑定服务端停止事件
        }

        #region 方法

        /// 绑定消息接收事件
        /// </summary>
        /// <param name="e"></param>
        private void Server_ApplicationMessageReceived(MqttApplicationMessageReceivedEventArgs e)
        {
            string msg = e.ApplicationMessage.ConvertPayloadToString();
            WriteLog(">>> 收到消息：" + msg + "，QoS =" + e.ApplicationMessage.QualityOfServiceLevel + "，客户端=" + e.ClientId + "，主题：" + e.ApplicationMessage.Topic);
        }

        /// <summary>
        /// 绑定客户端连接事件
        /// </summary>
        /// <param name="e"></param>
        private void Server_ClientConnected(MqttServerClientConnectedEventArgs e)
        {
            Task.Run(() =>
            {
                App.Current.Dispatcher.Invoke(() =>
                {
                    this.ClientsList.Add(e.ClientId);
                });
                WriteLog(">>> 客户端" + e.ClientId + "连接");
            });
        }

        /// <summary>
        /// 绑定客户端断开事件
        /// </summary>
        /// <param name="e"></param>
        private void Server_ClientDisconnected(MqttServerClientDisconnectedEventArgs e)
        {
            Task.Run(() =>
            {
                App.Current.Dispatcher.Invoke(() =>
                {
                    this.ClientsList.Remove(e.ClientId);
                });
                WriteLog(">>> 客户端" + e.ClientId + "断开");
            });
        }

        /// <summary>
        /// 绑定客户端订阅主题事件
        /// </summary>
        /// <param name="e"></param>
        private void Server_ClientSubscribedTopic(MqttServerClientSubscribedTopicEventArgs e)
        {
            Task.Run(() =>
            {
                App.Current.Dispatcher.Invoke(() =>
                {
                    var topic = Topics.FirstOrDefault(t => t.Topic == e.TopicFilter.Topic);
                    if (topic == null)
                    {
                        topic = new TopicItem { Topic = e.TopicFilter.Topic, Count = 0 };
                        Topics.Add(topic);
                    }
                    if (!topic.Clients.Exists(c => c == e.ClientId))
                    {
                        topic.Clients.Add(e.ClientId);
                        topic.Count++;
                    }

                    this.TopicsList.Clear();
                    foreach (var item in this.Topics)
                    {
                        this.TopicsList.Add($"{item.Topic}:{item.Count}");
                    }
                });
                WriteLog(">>> 客户端" + e.ClientId + "订阅主题" + e.TopicFilter.Topic);
            });
        }

        /// <summary>
        /// 绑定客户端退订主题事件
        /// </summary>
        /// <param name="e"></param>
        private void Server_ClientUnsubscribedTopic(MqttServerClientUnsubscribedTopicEventArgs e)
        {
            Task.Run(() =>
            {
                App.Current.Dispatcher.Invoke(() =>
                {
                    var topic = Topics.FirstOrDefault(t => t.Topic == e.TopicFilter);
                    if (topic != null)
                    {
                        topic.Count--;
                        topic.Clients.Remove(e.ClientId);
                    }

                    this.TopicsList.Clear();
                    foreach (var item in this.Topics)
                    {
                        this.TopicsList.Add($"{item.Topic}:{item.Count}");
                    }
                });
                WriteLog(">>> 客户端" + e.ClientId + "退订主题" + e.TopicFilter);
            });
        }

        /// <summary>
        /// 绑定服务端启动事件
        /// </summary>
        /// <param name="e"></param>
        private void Server_Started(EventArgs e)
        {
            WriteLog(">>> 服务端已启动！");
        }

        /// <summary>
        /// 绑定服务端停止事件
        /// </summary>
        /// <param name="e"></param>
        private void Server_Stopped(EventArgs e)
        {
            WriteLog(">>> 服务端已停止！");
        }

        /// <summary>
        /// 显示日志
        /// </summary>
        /// <param name="message"></param>
        public void WriteLog(string message)
        {
            Task.Run(() =>
            {
                App.Current.Dispatcher.Invoke(() =>
                {
                    ConnectWords = message + "\r";
                });
            });
        }

        #endregion



        #region 属性
        private MqttServerModel server = new MqttServerModel("127.0.0.1", "1869", "boss", "1234");//服务器实体
        /// <summary>
        /// 当前服务器对象
        /// </summary>
        public MqttServerModel Server
        {
            get { return server; }
            set
            {
                server = value;
                OnPropertyChanged();
            }
        }

        private string connectWords = "";
        /// <summary>
        /// 连接状态
        /// </summary>
        public string ConnectWords
        {
            get { return connectWords; }
            set
            {
                connectWords = value;
                OnPropertyChanged();
            }
        }

        private ObservableCollection<string> clientsList = new ObservableCollection<string>();
        /// <summary>
        /// 客户列表
        /// </summary>
        public ObservableCollection<string> ClientsList
        {
            get { return clientsList; }
            set
            {
                clientsList = value;
                OnPropertyChanged();
            }
        }

        private ObservableCollection<string> topicsList = new ObservableCollection<string>();
        /// <summary>
        /// 主题列表
        /// </summary>
        public ObservableCollection<string> TopicsList
        {
            get { return topicsList; }
            set
            {
                topicsList = value;
                OnPropertyChanged();
            }
        }
        #endregion




        #region 命令
        /// <summary>
        /// 启动命令
        /// </summary>
        [Obsolete]
        public ICommand StartCommand
        {
            get
            {
                return new RelayCommand(async o =>
                {
                    var optionBuilder = new MqttServerOptionsBuilder()
                .WithDefaultEndpointBoundIPAddress(System.Net.IPAddress.Parse(Server.ServerIP))
                .WithDefaultEndpointPort(int.Parse(Server.ServerPort))
                .WithDefaultCommunicationTimeout(TimeSpan.FromMilliseconds(5000))
                .WithConnectionValidator(t =>
                {
                    string un = "", pwd = "";
                    un = Server.ServerName;
                    pwd = Server.ServerPwd;
                    if (t.Username != un || t.Password != pwd)
                    {
                        t.ReturnCode = MqttConnectReturnCode.ConnectionRefusedBadUsernameOrPassword;
                    }
                    else
                    {
                        t.ReturnCode = MqttConnectReturnCode.ConnectionAccepted;
                    }
                });
                    var option = optionBuilder.Build();
                    //启动
                    await mqttserver.StartAsync(option);
                }
                );
            }
        }

        /// <summary>
        /// 启动命令
        /// </summary>
        [Obsolete]
        public ICommand StopCommand
        {
            get
            {
                return new RelayCommand(async o =>
                { 
                    if (server != null)
                    {
                        await mqttserver.StopAsync();
                    } 
                });
            }
        }
        #endregion

    }
}

 注意一个地方，就是给文本框添加了一个右键“清空”的功能，看看是怎么样实现的？

 6、启动测试服务器

启动成功，服务器kokokokoko！！！！

 3、客户端创建

1、添加项目MQTTNETClientWPF

2、添加客户端的组件

 

3、创建相关的类文件及目录 

 

4、设计UI布局

 布局仔细 看下

<Window x:Class="MQTTNETClientWPF.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:MQTTNETClientWPF.ViewModel"
              mc:Ignorable="d" Background="Transparent" WindowStartupLocation="CenterScreen"
        FontSize="13" FontFamily="Microsoft YaHei" FontWeight="ExtraLight" Foreground="#333"
        Title="MainWindow" Height="600" Width="850">
    <WindowChrome.WindowChrome>
        <WindowChrome GlassFrameThickness="-1"/>
    </WindowChrome.WindowChrome>
    <Window.DataContext>
        <local:MainWindowViewModel/>
    </Window.DataContext>
    <Grid  ShowGridLines="true" >
        <Grid.RowDefinitions>
            <RowDefinition Height="70"/>
            <RowDefinition/>
        </Grid.RowDefinitions>
        <TextBlock Grid.Row="0" FontWeight="Bold"  Text="WPF版MQTT客户端程序" FontSize="25" VerticalAlignment="Center" Margin="6,20,0,0" Foreground="#666" Background="BlanchedAlmond"  />

        <Grid Grid.Row="1">
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="220"/>
                <ColumnDefinition/>
            </Grid.ColumnDefinitions>
            <Border BorderBrush="#EEE" BorderThickness="0,0,1,0"/>

            <StackPanel Margin="20">
                <TextBlock Text="主机地址"/>
                <TextBox Text="{Binding Client.ServerIP}" Height="30" VerticalContentAlignment="Center" Padding="5,0" Margin="0,10" Name="tbHostAddr"/>
                <TextBlock Text="端口号" Margin="0,5,0,0"/>
                <TextBox  Text="{Binding Client.ServerPort}" Height="30" VerticalContentAlignment="Center" Padding="5,0" Margin="0,10"   Name="tbHostPort"/>
                <TextBlock Text="连接账号" Margin="0,5,0,0"/>
                <TextBox  Text="{Binding Client.ServerName}" Height="30" VerticalContentAlignment="Center" Padding="5,0" Margin="0,10" Name="tbUsername"/>
                <TextBlock Text="连接密码" Margin="0,5,0,0"/>
                <TextBox Text="{Binding Client.ServerPwd}" Height="30" VerticalContentAlignment="Center" Padding="5,0" Margin="0,10"  Name="tbPassword"/>
                <TextBlock Text="客户端ID" Margin="0,5,0,0"/>
                <TextBox Text="{Binding Client.ClientId}" Height="30" VerticalContentAlignment="Center" Padding="5,0" Margin="0,10"   Name="tbClientId"/>
                <Button Content="连接" Margin="0,30,0,0" Height="30" Command="{Binding OpenCommand}"  Style="{StaticResource ButtonStyle}"/>
                <Button Content="断开" Margin="0,10" Height="30"  Command="{Binding CloseCommand}" Style="{StaticResource ButtonStyle}"/>
            </StackPanel>

            <Grid Grid.Column="1" Margin="20,10">
                <Grid.RowDefinitions>
                    <RowDefinition Height="auto"/>
                    <RowDefinition Height="auto"/>
                    <RowDefinition/>
                </Grid.RowDefinitions>

                <Grid>
                    <Grid.RowDefinitions>
                        <RowDefinition Height="30"/>
                        <RowDefinition Height="50"/>
                    </Grid.RowDefinitions>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="auto"/>
                        <ColumnDefinition/>
                        <ColumnDefinition Width="auto"/>
                    </Grid.ColumnDefinitions>
                    <Border Background="#F7F9FA" Grid.ColumnSpan="3"/>
                    <TextBlock Text="订阅" VerticalAlignment="Center" Margin="5,0"/>
                    <TextBlock Text="主题" Grid.Row="1" VerticalAlignment="Center" HorizontalAlignment="Center" Margin="5,0"/>
                    <TextBox Text="{Binding Topic}" Grid.Row="1" Height="30" Padding="5,0" VerticalContentAlignment="Center" Grid.Column="1"  Name="tbTopic"/>
                    <Button Width="50" Grid.Row="1" Height="30" Content="订阅" Grid.Column="2" Margin="5,10,0,10"   Command="{Binding SubscriteCommand}"  Style="{StaticResource ButtonStyle}"  HorizontalAlignment="Left"/>
                </Grid>

                <Grid Grid.Row="1" Margin="0,20">
                    <Grid.RowDefinitions>
                        <RowDefinition Height="30"/>
                        <RowDefinition Height="50"/>
                        <RowDefinition Height="30"/>
                        <RowDefinition/>
                    </Grid.RowDefinitions>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="auto"/>
                        <ColumnDefinition/>
                        <ColumnDefinition Width="auto"/>
                    </Grid.ColumnDefinitions>
                    <Border Background="#F7F9FA" Grid.ColumnSpan="3"/>
                    <TextBlock Text="发布" VerticalAlignment="Center" Margin="5,0"/>
                    <TextBlock Text="主题" Grid.Row="1" VerticalAlignment="Center" HorizontalAlignment="Center" Margin="5,0"/>
                    <TextBox Text="{Binding Topic}" Grid.Row="1" Height="30" Padding="5,0" VerticalContentAlignment="Center" Grid.Column="1"   Name="tbPubTopic"/>
                    <TextBlock Text="内容" Grid.Row="2" VerticalAlignment="Center" HorizontalAlignment="Center" Margin="5,0"/>
                    <TextBox Text="{Binding Pubmsg}"  Grid.Row="2" Height="30" Padding="5,0" VerticalContentAlignment="Center" Grid.Column="1"  Name="tbContent"/>
                    <Button Width="50" Grid.Row="2" Height="30"  Content="发布" Grid.Column="2" Margin="5,0,5,0"  Command="{Binding PublishCommand}"  Style="{StaticResource ButtonStyle}"  VerticalAlignment="Top"/>
                </Grid>

                <Grid Grid.Row="2" Margin="0,10,0,0">
                    <Grid.RowDefinitions>
                        <RowDefinition Height="30"/>
                        <RowDefinition/>
                    </Grid.RowDefinitions>
                    <Border Background="#F7F9FA" Grid.ColumnSpan="3"/>
                    <TextBlock Text="消息" VerticalAlignment="Center" Margin="5,0"/>
                    <TextBox  Grid.Row="1"  x:Name="txtRich" ToolTip="右键清理内容" Text="{Binding ConnectWords}" Height="200"  Background="White" VerticalContentAlignment="Top"  Padding="3,0" Margin="10,9,75,10"  >
                        <!--添加一个右键菜单的功能，即清空-->
                        <TextBox.ContextMenu>
                            <ContextMenu>
                                <MenuItem x:Name="menuClear" Click="miClear_Click"  Header="清空内容"></MenuItem>
                            </ContextMenu>
                        </TextBox.ContextMenu>
                    </TextBox>
                </Grid>
            </Grid>
        </Grid>
    </Grid>
</Window>

5、视图模型viewmodel

模型类的属性绑定和命令绑定，数据驱动控件，即Mvvm渲染方法

using MQTTnet.Client.Options;
using MQTTnet.Client;
using MQTTnet.Extensions.ManagedClient;
using MQTTNETClientWPF.Command;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Input;
using MQTTNETClientWPF.Model;
using MQTTnet;

namespace MQTTNETClientWPF.ViewModel
{
    public class MainWindowViewModel : ViewModelBase
    {
        private IManagedMqttClient mqttClient; //mqtt客户端


        public MainWindowViewModel()
        {
            var factory = new MqttFactory();
            mqttClient = factory.CreateManagedMqttClient();//创建客户端对象

            //绑定断开事件
            mqttClient.UseDisconnectedHandler(async ee =>
            {
                WriteLog(DateTime.Now.ToString() + "与服务器之间的连接断开了，正在尝试重新连接");
                // 等待 5s 时间
                await Task.Delay(TimeSpan.FromSeconds(5));
                try
                {
                    mqttClient.UseConnectedHandler(cc =>
                    {
                        WriteLog(">>> 连接到服务成功！");
                    });
                }
                catch (Exception ex)
                {
                    Console.WriteLine($"重新连接服务器失败:{ex}");
                }
            });

            //绑定接收事件
            mqttClient.UseApplicationMessageReceivedHandler(aa =>
            {
                 try
                {
                    string msg = aa.ApplicationMessage.ConvertPayloadToString();
                    WriteLog(">>> 消息：" + msg + "，QoS =" + aa.ApplicationMessage.QualityOfServiceLevel + "，客户端=" + aa.ClientId + "，主题：" + aa.ApplicationMessage.Topic);
                }
                catch (Exception ex)
                {
                    WriteLog($"+ 消息 = " + ex.Message);
                } 
            });

            //绑定连接事件
            mqttClient.UseConnectedHandler(ee =>
            {
                WriteLog(">>> 连接到服务");
            });
        }

        /// <summary>
        /// 显示日志
        /// </summary>
        /// <param name="message"></param> 
        public void WriteLog(string message)
        {
            Task.Run(() =>
            {
                App.Current.Dispatcher.Invoke(() =>
                {
                    ConnectWords = message + "\r";
                });
            });
        }

        #region 属性

        private MqttClientModel client = new MqttClientModel("127.0.0.1", "1869", "boss", "1234", "c1");//服务器实体

        /// <summary>
        /// 连接对象
        /// </summary>
        public MqttClientModel Client
        {
            get { return client; }
            set
            {
                client = value;
                OnPropertyChanged();
            }
        }

        private string connectWords = "";
        /// <summary>
        /// 连接状态
        /// </summary>
        public string ConnectWords
        {
            get { return connectWords; }
            set
            {
                connectWords = value;
                OnPropertyChanged();
            }
        }

        private string topic = "shanghai";
        /// <summary>
        /// 主题
        /// </summary>
        public string Topic
        {
            get { return topic; }
            set
            {
                topic = value;
                OnPropertyChanged();
            }
        }

        private string pubmsg = "0103";
        /// <summary>
        /// 发布
        /// </summary>
        public string Pubmsg
        {
            get { return pubmsg; }
            set
            {
                pubmsg = value;
                OnPropertyChanged();
            }
        }
        #endregion


        #region 命令
        /// <summary>
        /// 连接命令
        /// </summary> 
        public ICommand OpenCommand
        {
            get
            {
                return new RelayCommand(async o =>
                {
                    var mqttClientOptions = new MqttClientOptionsBuilder()
                             .WithClientId(this.Client.ClientId)
                             .WithTcpServer(this.Client.ServerIP, int.Parse(this.Client.ServerPort))
                             .WithCredentials(this.Client.ServerName, this.Client.ServerPwd);

                    var options = new ManagedMqttClientOptionsBuilder()
                                .WithAutoReconnectDelay(TimeSpan.FromSeconds(5))
                                .WithClientOptions(mqttClientOptions.Build())
                                .Build();
                    //开启
                    var t = mqttClientOptions;
                    await mqttClient.StartAsync(options);
                });
            }
        }

        /// <summary>
        /// 断开命令
        /// </summary> 
        public ICommand CloseCommand
        {
            get
            {
                return new RelayCommand(async o =>
                {
                    if (mqttClient != null)
                    {
                        if (mqttClient.IsStarted)
                        {
                            await mqttClient.StopAsync();
                        }
                        mqttClient.Dispose();
                    }
                });
            }
        }

        /// <summary>
        /// 订阅命令
        /// </summary> 
        [Obsolete]
        public ICommand SubscriteCommand
        {
            get
            {
                return new RelayCommand(async o =>
                {
                    if (string.IsNullOrWhiteSpace(this.Topic))
                    {
                        WriteLog(">>> 请输入主题");
                        return;
                    }

                    //在 MQTT 中有三种 QoS 级别： 
                    //At most once(0) 最多一次
                    //At least once(1) 至少一次
                    //Exactly once(2) 恰好一次
                    //await mqttClient.SubscribeAsync(new TopicFilterBuilder().WithTopic(this.tbTopic.Text).WithAtMostOnceQoS().Build());//最多一次， QoS 级别0
                    await mqttClient.SubscribeAsync(new TopicFilterBuilder().WithTopic(this.Topic).WithAtLeastOnceQoS().Build());//恰好一次， QoS 级别1 

                    WriteLog($">>> 成功订阅 {this.Topic}");
                });
            }
        }

        /// <summary>
        /// 发布命令
        /// </summary> 
        public ICommand PublishCommand
        {
            get
            {
                return new RelayCommand(async o =>
                {
                    if (string.IsNullOrWhiteSpace(this.Topic))
                    {
                        WriteLog(">>> 请输入主题");
                        return;
                    }
                    var result = await mqttClient.PublishAsync(
                        this.Topic,
                        this.Pubmsg,
                        MQTTnet.Protocol.MqttQualityOfServiceLevel.AtLeastOnce);//恰好一次， QoS 级别1 
                    WriteLog($">>> 主题：{this.Topic}，消息：{this.Pubmsg}，结果： {result.ReasonCode}");
                });
            }
        }

        #endregion

    }
}

6、启动客户端

比较屌

4、测试mqtt

 

1、启动服务器，客户端连接成功

 2、测试订阅

3、测试发布

 再启动一个客户端程序，有人不知道如何启动，看下面

c1发布一个消息，看看c1,c2有没有收到，很明显都收到了

 服务器显示有关信息，完全good

基于mqttnet实现的wpf版通信，完美实现，效果飞起来了，颜值高，效果好，帅B得上了飞机。

5、完整代码打包下载 

链接：https://pan.baidu.com/s/1sfQnGEEcsRTBKUSDOdCeTA 
提取码：z2hj 

讲解不易，分析不易，原创不易，整理不易，伙伴们动动你的金手指，你的支持是我最大的动力。