MessageQueue.Exists(String) Method

public:
 static bool Exists(System::String ^ path);

public static bool Exists (string path);

static member Exists : string -> bool

Public Shared Function Exists (path As String) As Boolean

Parameters

Returns

true if a queue with the specified path exists; otherwise, false.

Exceptions

Examples

The following code example verifies whether a Message Queuing queue exists, and then deletes it.

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

using namespace System;
using namespace System::Messaging;
int main()
{
   
   // Determine whether the queue exists.
   if ( MessageQueue::Exists( ".\\myQueue" ) )
   {
      try
      {
         
         // Delete the queue.
         MessageQueue::Delete( ".\\myQueue" );
      }
      catch ( MessageQueueException^ e ) 
      {
         if ( e->MessageQueueErrorCode == MessageQueueErrorCode::AccessDenied )
         {
            Console::WriteLine( "Access is denied. Queue might be a system queue." );
         }
         
         // Handle other sources of MessageQueueException.
      }

   }

   return 0;
}

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 verifies existence and attempts to
        // delete a queue.
        //**************************************************

        public static void Main()
        {

            // Determine whether the queue exists.
            if (MessageQueue.Exists(".\\myQueue"))
            {
                try
                {
                    // Delete the queue.
                    MessageQueue.Delete(".\\myQueue");
                }
                catch(MessageQueueException e)
                {
                    if(e.MessageQueueErrorCode ==
                        MessageQueueErrorCode.AccessDenied)
                    {
                        Console.WriteLine("Access is denied. " +
                            "Queue might be a system queue.");
                    }

                    // Handle other sources of MessageQueueException.
                }
            }
        
            return;
        }
    }
}

Imports System.Messaging



Public Class MyNewQueue


        
        ' Provides an entry point into the application.
        '		 
        ' This example verifies existence and attempts to 
        ' delete a queue.
        

        Public Shared Sub Main()

            ' Determine whether the queue exists.
            If MessageQueue.Exists(".\myQueue") Then

                Try

                    ' Delete the queue.
                    MessageQueue.Delete(".\myQueue")

                Catch e As MessageQueueException

                    If e.MessageQueueErrorCode = _
                        MessageQueueErrorCode.AccessDenied Then

                        Console.WriteLine("Access is denied. " _
                            + "Queue might be a system queue.")
                    End If

                    ' Handle other sources of exceptions as necessary.

                End Try

            End If


            Return

        End Sub

End Class

Remarks

The Exists(String) method determines whether a Message Queuing queue exists at a specified path. No method exists to determine whether a queue with a specified format name exists. For more information about the format name syntax and other path syntax forms, see the Path property.)

Exists(String) is an expensive operation. Use it only when it is necessary within the application.

The syntax for the path parameter depends on the type of queue, as shown in the following table.

Exists(String) cannot be called to verify the existence of a remote private queue.

For more syntax, see the Path property.

Alternatively, you can use the Label to describe the queue path.

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

Applies to

See also

• Path