c# mqtt断线重连

以下是C#中实现MQTT断线重连的示例代码：

using System;
using System.Threading;
using MQTTnet;
using MQTTnet.Client;
using MQTTnet.Client.Options;
using MQTTnet.Client.Receiving;

class Program
{
    private static IMqttClient mqttClient;

    static async Task Main(string[] args)
    {
        var factory = new MqttFactory();        mqttClient = factory.CreateMqttClient();

        var options = new MqttClientOptionsBuilder()
            .WithTcpServer("broker.hivemq.com", 1883) // 设置MQTT服务器地址和端口
            .WithClientId("client1") // 设置客户端ID
            .Build();

        mqttClient.UseDisconnectedHandler(async e =>
        {
            Console.WriteLine("Disconnected from MQTT server. Trying to reconnect...");

            // 断线重连逻辑
            while (!mqttClient.IsConnected)
            {
                try
                {
                    await mqttClient.ConnectAsync(options); // 尝试重新连接
                    Console.WriteLine("Reconnected to MQTT server.");
                }
                catch (Exception ex)
                {
                    Console.WriteLine($"Failed to reconnect: {ex.Message}");
                    Thread.Sleep(5000); // 等待5秒后再次尝试连接
                }
            }
        });

        await mqttClient.ConnectAsync(options); // 连接到MQTT服务器

        // 订阅主题
        await mqttClient.SubscribeAsync(new MqttTopicFilterBuilder().WithTopic("topic1").Build());

        // 接收消息
        mqttClient.UseApplicationMessageReceivedHandler(e =>
        {
            Console.WriteLine($"Received message: {e.ApplicationMessage.Payload}");
        });

        Console.ReadLine();
    }
}

该示例代码中，我们使用了MQTTnet库来实现MQTT客户端的功能。在断线重连逻辑中，我们使用了一个循环来尝试重新连接，如果连接成功，则跳出循环。如果连接失败，则等待5秒后再次尝试连接。在断线重连过程中，我们可以根据需要进行异常处理或其他操作。