MessageQueueEnumerator Class

Reference

Definition

Namespace:: System.Messaging

Assembly:: System.Messaging.dll

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Provides a forward-only cursor to enumerate through messages in a message queue.

public ref class MessageQueueEnumerator : MarshalByRefObject, IDisposable, System::Collections::IEnumerator

public class MessageQueueEnumerator : MarshalByRefObject, IDisposable, System.Collections.IEnumerator

type MessageQueueEnumerator = class
    inherit MarshalByRefObject
    interface IEnumerator
    interface IDisposable

Public Class MessageQueueEnumerator
Inherits MarshalByRefObject
Implements IDisposable, IEnumerator

Inheritance: Object

MarshalByRefObject
MessageQueueEnumerator

Implements: IEnumerator IDisposable

Examples

The following code example iterates through all the message queues in the network, and examines the path for each queue. Finally, it displays the number of public queues on the network.

#using <System.dll>
#using <System.Messaging.dll>

using namespace System;
using namespace System::Messaging;

//**************************************************
// Iterates through message queues and examines the
// path for each queue. Also displays the number of
// public queues on the network.
//**************************************************
void ListPublicQueues()
{
   
   // Holds the count of private queues.
   int numberQueues = 0;
   
   // Get a cursor into the queues on the network.
   MessageQueueEnumerator^ myQueueEnumerator = MessageQueue::GetMessageQueueEnumerator();
   
   // Move to the next queue and read its path.
   while ( myQueueEnumerator->MoveNext() )
   {
      
      // Increase the count if priority is Lowest.
      Console::WriteLine( myQueueEnumerator->Current->Path );
      numberQueues++;
   }

   
   // Display final count.
   Console::WriteLine( "Number of public queues: {0}", numberQueues );
   return;
}


//**************************************************
// Provides an entry point into the application.
//   
// This example uses a cursor to step through the
// message queues and list the public queues on the
// network.
//**************************************************
int main()
{
   
   // Output the count of Lowest priority messages.
   ListPublicQueues();
}

using System;
using System.Messaging;

namespace MyProject
{
    /// <summary>
    /// Provides a container class for the example.
    /// </summary>
    public class MyNewQueue
    {

        //**************************************************
        // Provides an entry point into the application.
        //		
        // This example uses a cursor to step through the
        // message queues and list the public queues on the
        // network.
        //**************************************************

        public static void Main()
        {
            // Create a new instance of the class.
            MyNewQueue myNewQueue = new MyNewQueue();

            // Output the count of Lowest priority messages.
            myNewQueue.ListPublicQueues();
                        
            return;
        }

        //**************************************************
        // Iterates through message queues and examines the
        // path for each queue. Also displays the number of
        // public queues on the network.
        //**************************************************
        
        public void ListPublicQueues()
        {
            // Holds the count of private queues.
            uint numberQueues = 0;
    
            // Get a cursor into the queues on the network.
            MessageQueueEnumerator myQueueEnumerator =
                MessageQueue.GetMessageQueueEnumerator();

            // Move to the next queue and read its path.
            while(myQueueEnumerator.MoveNext())
            {
                // Increase the count if priority is Lowest.
                Console.WriteLine(myQueueEnumerator.Current.Path);
                numberQueues++;
            }

            // Display final count.
            Console.WriteLine("Number of public queues: " +
                numberQueues.ToString());
            
            return;
        }
    }
}

Imports System.Messaging



Public Class MyNewQueue


        
        ' Provides an entry point into the application.
        '		 
        ' This example uses a cursor to step through the
        ' message queues and list the public queues on the
        ' network.
        

        Public Shared Sub Main()

            ' Create a new instance of the class.
            Dim myNewQueue As New MyNewQueue()

            ' Output the count of Lowest priority messages.
            myNewQueue.ListPublicQueues()

            Return

        End Sub


        
        ' Iterates through message queues and examines the
        ' path for each queue. Also displays the number of
        ' public queues on the network.
        

        Public Sub ListPublicQueues()

            ' Holds the count of private queues.
            Dim numberQueues As Int32 = 0

            ' Get a cursor into the queues on the network.
            Dim myQueueEnumerator As MessageQueueEnumerator = _
                MessageQueue.GetMessageQueueEnumerator()

            ' Move to the next queue and read its path.
            While myQueueEnumerator.MoveNext()
                ' Increase the count if the priority is Lowest.
                Console.WriteLine(myQueueEnumerator.Current.Path)
                numberQueues += 1
            End While

            ' Display final count.
            Console.WriteLine(("Number of public queues: " + _
                numberQueues.ToString()))

            Return

        End Sub

End Class

Remarks

Use MessageQueueEnumerator for dynamic interaction with queues on the network. Methods available through the MessageQueue class can return either a MessageQueueEnumerator containing a dynamic list of queues, or an array that contains a snapshot of the queue collection at the time the specified method was called.

There is no defined ordering of queues in a network. They are not ordered, for example, by computer, label, public or private status, or other user-accessible criteria. A MessageQueueEnumerator is a cursor, initialized to the head of a dynamic list. You can move the cursor to the first queue of the enumeration by calling MoveNext. After the enumerator has been initialized, you can use MoveNext to step forward through the remaining queues.

It is not possible to step backward with a MessageQueueEnumerator. A cursor only allows forward movement through the queue enumeration. However, you can call Reset to reset the enumeration and put the cursor at the beginning of the list again. Because the enumerator is dynamic, a queue that is appended beyond the cursor's current position can be accessed by the enumerator. A queue that is inserted before the cursor's current position cannot be accessed without first calling Reset.

Properties

Current	Gets the current MessageQueue of the enumeration.
LocatorHandle	Gets the native Message Queuing handle used to locate queues in a network.

Methods

Close()	Frees the resources associated with the enumerator.
CreateObjRef(Type)	Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object. (Inherited from MarshalByRefObject)
Dispose()	Releases all resources used by the MessageQueueEnumerator.
Dispose(Boolean)	Releases the unmanaged resources used by the MessageQueueEnumerator and optionally releases the managed resources.
Equals(Object)	Determines whether the specified object is equal to the current object. (Inherited from Object)
Finalize()	Releases the resources held by the queue.
GetHashCode()	Serves as the default hash function. (Inherited from Object)
GetLifetimeService()	Obsolete. Retrieves the current lifetime service object that controls the lifetime policy for this instance. (Inherited from MarshalByRefObject)
GetType()	Gets the Type of the current instance. (Inherited from Object)
InitializeLifetimeService()	Obsolete. Obtains a lifetime service object to control the lifetime policy for this instance. (Inherited from MarshalByRefObject)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
MemberwiseClone(Boolean)	Creates a shallow copy of the current MarshalByRefObject object. (Inherited from MarshalByRefObject)
MoveNext()	Advances the enumerator to the next queue of the enumeration, if one is currently available.
Reset()	Resets the cursor, so it points to the beginning of the enumeration.
ToString()	Returns a string that represents the current object. (Inherited from Object)

Explicit Interface Implementations

IEnumerator.Current

Gets the current MessageQueue of the enumeration.

Applies to

Jaa