MessageQueue::GetMessageEnumerator Method ()

 
Note: This API is now obsolete.

Creates an enumerator object for all the messages in the queue. GetMessageEnumerator is deprecated. GetMessageEnumerator2 should be used instead.

Namespace:   System.Messaging
Assembly:  System.Messaging (in System.Messaging.dll)

public:
[ObsoleteAttribute("This method returns a MessageEnumerator that implements RemoveCurrent family of methods incorrectly. Please use GetMessageEnumerator2 instead.")]
MessageEnumerator^ GetMessageEnumerator()

Return Value

Type: System.Messaging::MessageEnumerator^

The MessageEnumerator holding the messages that are contained in the queue.

GetMessageEnumerator creates a dynamic list of all the messages in a queue. You can remove from the queue the message at the enumerator's current position by calling RemoveCurrent for the MessageEnumerator that GetMessageEnumerator returns.

Because the cursor is associated with the dynamic list of messages in the queue, the enumeration reflects any modification you make to the messages in the queue, if the message is beyond the current cursor position. For example, the enumerator can automatically access a lower-priority message placed beyond the cursor's current position, but not a higher-priority message inserted before that position. However, you can reset the enumeration, thereby moving the cursor back to the beginning of the list, by calling Reset for the MessageEnumerator.

The order of the messages in the enumeration reflects their order in the queue, so higher-priority messages will appear before lower-priority ones.

If you want a static snapshot of the messages in the queue rather than a dynamic connection to them, call GetAllMessages. This method returns an array of Message objects, which represent the messages at the time the method was called.

The following table shows whether this method is available in various Workgroup modes.

Workgroup mode

Available

Local computer

Yes

Local computer and direct format name

Yes

Remote computer

Yes

Remote computer and direct format name

Yes

The following code example gets a dynamic list of messages in a queue and counts all messages with the Priority property set to MessagePriority::Lowest.

#using <system.dll>
#using <system.messaging.dll>

using namespace System;
using namespace System::Messaging;
ref class MyNewQueue
{
public:
   void CountLowestPriority()
   {

      // Holds the count of Lowest priority messages.
      UInt32 numberItems = 0;

      // Connect to a queue.
      MessageQueue^ myQueue = gcnew MessageQueue( ".\\myQueue" );

      // Get a cursor into the messages in the queue.
      MessageEnumerator^ myEnumerator = myQueue->GetMessageEnumerator();

      // Specify that the messages's priority should be read.
      myQueue->MessageReadPropertyFilter->Priority = true;

      // Move to the next message and examine its priority.
      while ( myEnumerator->MoveNext() )
      {

         // Increase the count if priority is Lowest.
         if ( myEnumerator->Current->Priority == MessagePriority::Lowest )
                  numberItems++;
      }


      // Display final count.
      Console::WriteLine( "Lowest priority messages: {0}", numberItems );
      return;
   }

};

int main()
{

   // Create a new instance of the class.
   MyNewQueue^ myNewQueue = gcnew MyNewQueue;

   // Output the count of Lowest priority messages.
   myNewQueue->CountLowestPriority();
   return 0;
}

.NET Framework
Available since 1.1
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