The other day I answered a question on StackOverflow about subscribing to a topic using C# .NET code. I figured I should also post the code here for everyone to read & use.

You can download the source code from here.

using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
using System.Threading;
using IBM.WMQ;

/// <summary> Program Name
/// MQTest82
///
/// Description
/// This C# class will connect to a remote queue manager
/// and get messages from a topic using a managed .NET environment.
///
/// Sample Command Line Parameters
/// -h 127.0.0.1 -p 1414 -c TEST.CHL -m MQA1 -t abc/xyz -u tester -x mypwd
/// </summary>
/// <author>  Roger Lacroix
/// </author>
namespace MQTest82
{
   public class MQTest82
   {
      private Hashtable inParms = null;
      private Hashtable qMgrProp = null;
      private System.String qManager;
      private System.String topicString;

      /*
      * The constructor
      */
      public MQTest82()
          : base()
      {
      }

      /// <summary> Make sure the required parameters are present.</summary>
      /// <returns> true/false
      /// </returns>
      private bool allParamsPresent()
      {
         bool b = inParms.ContainsKey("-h") && inParms.ContainsKey("-p") &&
                  inParms.ContainsKey("-c") && inParms.ContainsKey("-m") &&
                  inParms.ContainsKey("-t");
         if (b)
         {
            try
            {
               System.Int32.Parse((System.String)inParms["-p"]);
            }
            catch (System.FormatException e)
            {
               b = false;
            }
         }

         return b;
      }

      /// <summary> Extract the command-line parameters and initialize the MQ variables.</summary>
      /// <param name="args">
      /// </param>
      /// <throws>  IllegalArgumentException </throws>
      private void init(System.String[] args)
      {
         inParms = System.Collections.Hashtable.Synchronized(new System.Collections.Hashtable(14));
         if (args.Length > 0 && (args.Length % 2) == 0)
         {
            for (int i = 0; i < args.Length; i += 2)
            {
               inParms[args[i]] = args[i + 1];
            }
         }
         else
         {
            throw new System.ArgumentException();
         }

         if (allParamsPresent())
         {
            qManager = ((System.String)inParms["-m"]);
            topicString = ((System.String)inParms["-t"]);

            qMgrProp = new Hashtable();
            qMgrProp.Add(MQC.TRANSPORT_PROPERTY, MQC.TRANSPORT_MQSERIES_MANAGED);

            qMgrProp.Add(MQC.HOST_NAME_PROPERTY, ((System.String)inParms["-h"]));
            qMgrProp.Add(MQC.CHANNEL_PROPERTY, ((System.String)inParms["-c"]));

            try
            {
               qMgrProp.Add(MQC.PORT_PROPERTY, System.Int32.Parse((System.String)inParms["-p"]));
            }
            catch (System.FormatException e)
            {
               qMgrProp.Add(MQC.PORT_PROPERTY, 1414);
            }

            if (inParms.ContainsKey("-u"))
               qMgrProp.Add(MQC.USER_ID_PROPERTY, ((System.String)inParms["-u"]));

            if (inParms.ContainsKey("-x"))
               qMgrProp.Add(MQC.PASSWORD_PROPERTY, ((System.String)inParms["-x"]));

            logger("Parameters:");
            logger("  QMgrName ='" + qManager + "'");
            logger("  Topic String ='" + topicString + "'");

            logger("Connection values:");
            foreach (DictionaryEntry de in qMgrProp)
            {
               logger("  " + de.Key + " = '" + de.Value + "'");
            }
         }
         else
         {
            throw new System.ArgumentException();
         }
      }

      /// <summary> Connect, open topic, get messages, close topic and disconnect. </summary>
      ///
      private void testReceive()
      {
         MQQueueManager qMgr = null;
         MQTopic inTopic = null;
         int openOptionsForGet = MQC.MQSO_CREATE | MQC.MQSO_FAIL_IF_QUIESCING | MQC.MQSO_MANAGED | MQC.MQSO_NON_DURABLE;

         try
         {
            qMgr = new MQQueueManager(qManager, qMgrProp);
            logger("successfully connected to " + qManager);

            inTopic = qMgr.AccessTopic(topicString, null, MQC.MQTOPIC_OPEN_AS_SUBSCRIPTION, openOptionsForGet);
            logger("successfully opened " + topicString);

            testLoop(inTopic);
         }
         catch (MQException mqex)
         {
            logger("CC=" + mqex.CompletionCode + " : RC=" + mqex.ReasonCode);
         }
         catch (System.IO.IOException ioex)
         {
            logger("ioex=" + ioex);
         }
         finally
         {
            try
            {
               if (inTopic != null)
                  inTopic.Close();
               logger("closed: " + topicString);
            }
            catch (MQException mqex)
            {
               logger("CC=" + mqex.CompletionCode + " : RC=" + mqex.ReasonCode);
            }

            try
            {
               if (qMgr != null)
                  qMgr.Disconnect();
               logger("disconnected from " + qManager);
            }
            catch (MQException mqex)
            {
               logger("CC=" + mqex.CompletionCode + " : RC=" + mqex.ReasonCode);
            }
         }
      }

      private void testLoop(MQTopic inTopic)
      {
         bool flag = true;
         MQGetMessageOptions gmo = new MQGetMessageOptions();
         gmo.Options |= MQC.MQGMO_NO_WAIT | MQC.MQGMO_FAIL_IF_QUIESCING;
         MQMessage msg = null;

         while (flag)
         {
            try
            {
               msg = new MQMessage();
               inTopic.Get(msg, gmo);
               if (msg.Feedback == MQC.MQFB_QUIT)
               {
                  flag = false;
                  logger("received quit message - exiting loop");
               }
               else
                  logger("Message Data: " + msg.ReadString(msg.MessageLength));
            }
            catch (MQException mqex)
            {
               logger("CC=" + mqex.CompletionCode + " : RC=" + mqex.ReasonCode);
               if (mqex.Reason == MQC.MQRC_NO_MSG_AVAILABLE)
               {
                  // no meesage - life is good - loop again
                  logger("sleeping");
                  Thread.Sleep(60*1000);  // sleep for 60 seconds
               }
               else
               {
                  flag = false;  // severe error - time to exit
               }
            }
            catch (System.IO.IOException ioex)
            {
               logger("ioex=" + ioex);
            }
         }
      }

      private void logger(String data)
      {
         DateTime myDateTime = DateTime.Now;
         System.Console.Out.WriteLine(myDateTime.ToString("yyyy/MM/dd HH:mm:ss.fff") + " " + this.GetType().Name + ": " + data);
      }

      /// <summary> main line</summary>
      /// <param name="args">
      /// </param>
      //        [STAThread]
      public static void Main(System.String[] args)
      {
         MQTest82 write = new MQTest82();

         try
         {
            write.init(args);
            write.testReceive();
         }
         catch (System.ArgumentException e)
         {
            System.Console.Out.WriteLine("Usage: MQTest82 -h host -p port -c channel -m QueueManagerName -t topicString [-u userID] [-x passwd]");
            System.Environment.Exit(1);
         }
         catch (MQException e)
         {
            System.Console.Out.WriteLine(e);
            System.Environment.Exit(1);
         }

         System.Environment.Exit(0);
      }
   }
}

Regards,
Roger Lacroix
Capitalware Inc.