C mqtt subscription message

Internet of things data communication , From the server mqtt Subscribe to data on the server ,

xml The format is as follows :

<?xml version="1.0" encoding="utf-8"?>
<Order>
  <Items>
    <Mqtt Ip="121.43.168.148"   Port="6000" Name="Data0" password="0"/>
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data0" startid="0" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data1" startid="1" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data2" startid="2" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data3" startid="3" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data4" startid="4" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data5" startid="5" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data6" startid="6" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data7" startid="7" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data8" startid="8" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data9" startid="9" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data10" startid="10" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data11" startid="11" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data12" startid="12" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data13" startid="13" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data14" startid="14" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data15" startid="15" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data16" startid="16" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data17" startid="17" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data18" startid="18" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data19" startid="19" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data20" startid="20" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data21" startid="21" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data22" startid="22" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data23" startid="23" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data24" startid="24" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data25" startid="25" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data26" startid="26" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data27" startid="27" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data28" startid="28" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data29" startid="29" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data30" startid="30" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data31" startid="31" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data32" startid="32" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data33" startid="33" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data34" startid="34" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data35" startid="35" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data36" startid="36" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data37" startid="37" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data38" startid="38" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data39" startid="39" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data40" startid="40" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data41" startid="41" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data42" startid="42" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data43" startid="43" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data44" startid="44" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data45" startid="45" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data46" startid="46" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data47" startid="47" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data48" startid="48" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data49" startid="49" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data50" startid="50" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data51" startid="51" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data52" startid="52" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data53" startid="53" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data54" startid="54" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data55" startid="55" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data56" startid="56" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data57" startid="57" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data58" startid="58" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data59" startid="59" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data60" startid="60" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data61" startid="61" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data62" startid="62" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data63" startid="63" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data64" startid="64" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data65" startid="65" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data66" startid="66" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data67" startid="67" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data68" startid="68" numid="10" note="10" Value="10" />
    <OrderItem Room="1# Power distribution room " Line=" Incoming cabinet " Name="Data69" startid="69" numid="10" note="10" Value="10" />

  </Items>
</Order>

The subscription topic is 1# Power distribution room / Incoming cabinet /Data0 etc.

The following figure shows how to subscribe to some data

Subscription code :

 string topic = "/home/tempurture/line1";

            MqttClient client = new MqttClient(serverIp, Convert.ToInt32(serverPort), false, null, null, MqttSslProtocols.TLSv1_2);
            string clientId = Guid.NewGuid().ToString();
            string username = "admin";
            string password = "password";
            // Establishing a connection
            client.Connect(clientId, username, password);
            for (int m = 0; m < xml.datalist.Count; m++)
            {
                topic = xml.datalist[m];
                // Subscribe to topics "/home/temperature", Subscription quality QoS 2 
                client.Subscribe(new string[] { topic }, new byte[] { MqttMsgBase.QOS_LEVEL_EXACTLY_ONCE });
            }
            label1.Text = topic;
            client.MqttMsgPublishReceived += new MqttClient.MqttMsgPublishEventHandler(messageReceive);
            timer1.Interval = Convert.ToInt32(textStartId.Text) * 1000 + 30000;
            this.timer1.Enabled = true;

  If you need the source code, send it to my email ,[email protected]