Mqtt publish/subscribe using c#

Question

I've already worked with mqtt in Java. Now I need to create a C# application to subcribe and publish mqtt messages.

using MqttDotNet library

IMqtt _client = MqttClientFactory.CreateClient(connectionString, clientId);

What is the connectionString?

using M2Mqtt library

The connection succeeded, but I did not receive any published messages.

This is my code:

class Program
{
    static void Main(string[] args)
    {
        var client = new MqttClient(IPAddress.Parse("myTestIP"));

        // register to message received
        client.MqttMsgPublishReceived += client_MqttMsgPublishReceived;

        var clientId = Guid.NewGuid().ToString();
        client.Connect(clientId);

        // subscribe to the topic "/home/temperature" with QoS 2
        client.Subscribe(
            new string[] {"testTopic"},
            new byte[] { MqttMsgBase.QOS_LEVEL_EXACTLY_ONCE });
    }

    static void client_MqttMsgPublishReceived(
        object sender, MqttMsgPublishEventArgs e)
    {
        // handle message received
        Console.WriteLine("message=" + e.Message.ToString());
    }
}

This my message publishing code:

mosquitto_pub -d -h testIp  -t "testTopic" -m "haai"

Answer 1

I don't think that the MqttDotNet is currently mantained. I could suggest to use my M2Mqtt client and found documentation on official web site here : https://m2mqtt.wordpress.com/

The M2Mqtt client is available on Nuget as package too here : https://www.nuget.org/packages/M2Mqtt/

Paolo.