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How Do I...Receive a message from a message queue?



Message queuing makes it easy for application developers to communicate with application programs quickly and reliably by sending and receiving messages. Messaging provides you with guaranteed message delivery and a robust, fail-safe way to carry out many of your business processes.

The MessageQueue component allows you to easily incorporate message-based communication into your applications. Using this component and its associated language features, you can send and receive messages, explore existing queues, create and delete queues, and perform a variety of other operations using a simple programming model.

The sample illustrates how to use the MessageQueue component to receive a message from a message queue. To run the sample you have to have Message Queuing installed on your system. The sample is a command-line application that takes one command-line argument. The argument is the name of a public message queue on your local machine. For example, you can run it as follows (first send a message to the queue using the MQSend sample): 
> MQReceive.exe MyQueue
The sample application will receive and output to the console the first message from the queue. In its simplest form, receiving a message from a message queue involves:
  1. Creating an instance of the MessageQueue component, setting its Path, and initializing the Formatter's TargetTypeNames property:

    MessageQueue mq = new MessageQueue(".\\MyQueue"); string[] types = { "System.String" }; ((XmlMessageFormatter)mq.Formatter).TargetTypeNames = types; Dim mq As MessageQueue = new MessageQueue(mqPath) Dim formatter As XmlMessageFormatter = CType(mq.Formatter,XmlMessageFormatter) formatter.TargetTypeNames = new String(){"System.String"} MessageQueue* mq = new MessageQueue(mqPath); String* strTypeNames[] = { S"System.String,mscorlib" }; __try_cast( mq->Formatter )->TargetTypeNames = strTypeNames;


  2. Calling Receive to receive the message:

    Message m = mq.Receive(new TimeSpan(0,0,3)); Console.WriteLine((string)m.Body); Dim m As Message = mq.Receive(New TimeSpan(0,0,3)) Console.WriteLine(CStr(m.Body)) Message* m = mq->Receive( TimeSpan(0,0,3) ); Console::WriteLine( String::Concat( S"Message: ", __try_cast(m->Body) ) );

Example