WPF真入门教程28--项目案例--MQTT服务器和客户端

1、先上图看帅照

这个案例还是布局加视图模型，样式应用，业务逻辑，该项目是一个mqtt服务器和客户端的通信工具，这里不去分析mqtt的通信原理，关注在于wpf技能的应用，能够掌握这个例子，离项目开发也差不多了，只是没有跟db打交道，本项目重点在于理解mvvm模式，开发环境依然是vs2022，.netframework 4.8，wpf应用程序。

默认启动的效果

最大化的效果，控件没有变形没有走样，说明wpf的技术还是不错的，界面没有变形，不象winform，控件会走样。

2、服务器这么搞

1、创建项目

2、添加包组件MQTTNET

3、创建相关的目录及文件

4、设置UI布局界面

完全代码：

5、视图模型，属性绑定和命令绑定

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 Topics = new List();

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

        #region 方法

        /// 绑定消息接收事件
        /// 
        /// 
        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);
        }

        /// 
        /// 绑定客户端连接事件
        /// 
        /// 
        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");
            });
        }

        /// 
        /// 绑定客户端断开事件
        /// 
        /// 
        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");
            });
        }

        /// 
        /// 绑定客户端订阅主题事件
        /// 
        /// 
        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);
            });
        }

        /// 
        /// 绑定客户端退订主题事件
        /// 
        /// 
        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);
            });
        }

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

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

        /// 
        /// 显示日志
        /// 
        /// 
        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
        /// 
        /// 当前服务器对象
        /// 
        public MqttServerModel Server
        {
            get { return server; }
            set
            {
                server = value;
                OnPropertyChanged();
            }
        }

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

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

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




        #region 命令
        /// 
        /// 启动命令
        /// 
        [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);
                }
                );
            }
        }

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

    }
}

1）属性绑定

2）视图绑定

3）命令绑定

4）样式应用

6、启动看效果

3、客户端跟着搞

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

完整代码：