C# 基于.NET Framework框架WPF应用程序-MQTTNet库实现MQTT消息订阅发布

MQTT简述
MQTTNet简述
创建项目（基于.NET Framework框架）
安装MQTTNet库
项目源码
运行效果

MQTT简述

mqtt官网
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MQTTNet简述

MQTTnet
MQTTnet 是一个强大的开源 MQTT 客户端库，适用于 C# 平台。它提供了丰富的功能和灵活的 API，可以轻松地构建基于 MQTT 协议的应用程序。

创建项目（基于.NET Framework框架）

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安装MQTTNet库

NuGet包管理器搜索MQTTNet

项目源码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;using MQTTnet;
using MQTTnet.Client;
using MQTTnet.Server;
using MQTTnet.Adapter;
using MQTTnet.Protocol;
using MQTTnet.Formatter;
using MQTTnet.Extensions;namespace MQTTNetDemo
{/// <summary>/// MainWindow.xaml 的交互逻辑/// </summary>public partial class MainWindow : Window{public string STR_MQTT_HOST = "mqtt borker host"; // MQTT borker addresspublic string STR_MQTT_USERNAME = "your username";public string STR_MQTT_PASSWORD = "your password";public string STR_MQTT_CLINETID = "mqtt clientid";public string STR_MQTT_SUBTOPIC = "topic_device"; // 订阅Topicpublic string STR_MQTT_PUBTOPIC = "topic_server"; // 发布Topicprivate MqttFactory mqttFactory = new MqttFactory();    // 创建MQTT工厂实例private IMqttClient mqttClient = null;  // 定义MqttClient接口public MainWindow(){InitializeComponent();}/// <summary>/// 连接MQTT服务/// </summary>/// <returns></returns>private async Task UserMqttConnect(){ mqttClient = mqttFactory.CreateMqttClient();var mqttClientOptions = new MqttClientOptionsBuilder().WithTcpServer(STR_MQTT_HOST, 1883).WithCredentials(STR_MQTT_USERNAME, STR_MQTT_PASSWORD).WithClientId(STR_MQTT_CLINETID).WithCleanSession(true).Build();var response = await mqttClient.ConnectAsync(mqttClientOptions);Console.WriteLine("The MQTT Client is connected.");Console.WriteLine(response.ToString());}/// <summary>/// 断开MQTT服务/// </summary>/// <returns></returns>private async Task UserMqttDisconnect(){await mqttClient.DisconnectAsync();mqttClient.Dispose();Console.WriteLine("The MQTT Client is Disconnected.");            }/// <summary>/// MQTT发布消息/// </summary>/// <param name="payload">消息内容</param>/// <returns></returns>public async Task UserMqttPublishMessage(string payload){if (mqttClient != null && mqttClient.IsConnected == true){var publishPacket = new MqttApplicationMessageBuilder().WithTopic(STR_MQTT_PUBTOPIC).WithPayload(payload).WithQualityOfServiceLevel(MqttQualityOfServiceLevel.ExactlyOnce).Build();//MqttQualityOfServiceLevel.AtMostOnce;//MqttQualityOfServiceLevel.AtLeastOnce//MqttQualityOfServiceLevel.ExactlyOnce;await mqttClient.PublishAsync(publishPacket);}else{MessageBox.Show("MQTT Client is Disconnected!");}}/// <summary>/// MQTT订阅消息/// </summary>/// <returns></returns>private async Task UserMqttSubscribeMessage(){await mqttClient.SubscribeAsync(new MqttTopicFilterBuilder().WithTopic(STR_MQTT_SUBTOPIC).WithQualityOfServiceLevel(MqttQualityOfServiceLevel.AtLeastOnce).Build());mqttClient.ApplicationMessageReceivedAsync += delegate (MqttApplicationMessageReceivedEventArgs args){// TODO: 解析订阅消息payload内容var payload = Encoding.UTF8.GetString(args.ApplicationMessage.PayloadSegment.Array);Console.WriteLine("Recv Message:" + payload);Console.WriteLine("Recv ClientID:" + args.ClientId);Console.WriteLine("Recv Topic:" + args.ApplicationMessage.Topic);Console.WriteLine("Recv Retain:" + args.ApplicationMessage.Retain); // 指示消息是否为保留消息Console.WriteLine("Recv QOS:" + args.ApplicationMessage.QualityOfServiceLevel);// Now respond to the broker with a reason code other than success.args.ReasonCode = MqttApplicationMessageReceivedReasonCode.ImplementationSpecificError;args.ResponseReasonString = "That did not work!";// User properties require MQTT V5!args.ResponseUserProperties.Add(new MQTTnet.Packets.MqttUserProperty("My", "Data"));// Now the broker will resend the message again;return Task.CompletedTask;};Console.WriteLine("The MQTT is subscribe ...\n");}private async void btnMqttConnect_Click(object sender, RoutedEventArgs e){await UserMqttConnect();}private async void btnMqttDisconnect_Click(object sender, RoutedEventArgs e){await UserMqttDisconnect();}private async void btnMqttSubscribe_Click(object sender, RoutedEventArgs e){await UserMqttSubscribeMessage();}private async void btnMqttPublish_Click(object sender, RoutedEventArgs e){if ("" != textBoxMqttPublishMessage.Text){string payload = textBoxMqttPublishMessage.Text.ToString();await UserMqttPublishMessage(payload);}else{MessageBox.Show("发布消息内容为空！");}            }}
}