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MessageQueue.GetPublicQueuesByCategory Method

Retrieves all the public queues on the network that belong to the specified category.

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

'Declaration
Public Shared Function GetPublicQueuesByCategory ( _
	category As Guid _
) As MessageQueue()

Parameters

category
Type: System.Guid

A Guid that groups the set of queues to be retrieved.

Return Value

Type: System.Messaging.MessageQueue()
An array of MessageQueue objects that reference the retrieved public queues.

ExceptionCondition
MessageQueueException

An error occurred when accessing a Message Queuing method.

Use this method to filter the public queues by category. The Category property provides access to the Message Queuing type ID property (which is read/write) of a particular queue. Although you can use NewGuid to create a category value that is unique across all Guid values, it is not necessary. The category value needs to be distinct only from other categories, not from all other Guid values. For example, you can assign {00000000-0000-0000-0000-000000000001} as the Category for one set of queues and {00000000-0000-0000-0000-000000000002} as the Category for another set.

GetPublicQueuesByCategory(Guid) retrieves a static snapshot of the queues. To interact with a dynamic list of the queues, use GetMessageQueueEnumerator. You can specify the category as part of the MessageQueueCriteria you pass into the method.

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

Workgroup mode

Available

Local computer

No

Local computer and direct format name

No

Remote computer

No

Remote computer and direct format name

No

The following code example retrieves lists of queues.

Imports System
Imports System.Messaging

Public Class MyNewQueue



        ' Provides an entry point into the application. 
        '		  
        ' This example gets lists of queues by a variety 
        ' of criteria. 


        Public Shared Sub Main()

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

            ' Send normal and high priority messages.
            myNewQueue.GetQueuesByCategory()
            myNewQueue.GetQueuesByLabel()
            myNewQueue.GetQueuesByComputer()
            myNewQueue.GetAllPublicQueues()
            myNewQueue.GetPublicQueuesByCriteria()
            myNewQueue.GetPrivateQueues()

            Return 

        End Sub 'Main



        ' Gets a list of queues with a specified category. 
        ' Sends a broadcast message to all queues in that 
        ' category. 

        Public Sub GetQueuesByCategory()

            ' Get a list of queues with the specified category. 
            Dim QueueList As MessageQueue() = _
                MessageQueue.GetPublicQueuesByCategory(New _
                Guid("{00000000-0000-0000-0000-000000000001}"))

            ' Send a broadcast message to each queue in the array. 
            Dim queueItem As MessageQueue
            For Each queueItem In QueueList
                queueItem.Send("Broadcast message.")
            Next queueItem

            Return 

        End Sub 'GetQueuesByCategory



        ' Gets a list of queues with a specified label. 
        ' Sends a broadcast message to all queues with that 
        ' label. 


        Public Sub GetQueuesByLabel()

            ' Get a list of queues with the specified label. 
            Dim QueueList As MessageQueue() = _
                MessageQueue.GetPublicQueuesByLabel("My Label")

            ' Send a broadcast message to each queue in the array. 
            Dim queueItem As MessageQueue
            For Each queueItem In QueueList
                queueItem.Send("Broadcast message.")
            Next queueItem

            Return 

        End Sub 'GetQueuesByLabel



        ' Gets a list of queues on a specified computer.  
        ' Displays the list on screen. 


        Public Sub GetQueuesByComputer()

            ' Get a list of queues on the specified computer. 
            Dim QueueList As MessageQueue() = _
                MessageQueue.GetPublicQueuesByMachine("MyComputer")

            ' Display the paths of the queues in the list. 
            Dim queueItem As MessageQueue
            For Each queueItem In QueueList
                Console.WriteLine(queueItem.Path)
            Next queueItem

            Return 

        End Sub 'GetQueuesByComputer



        ' Gets a list of all public queues. 


        Public Sub GetAllPublicQueues()

            ' Get a list of public queues. 
            Dim QueueList As MessageQueue() = _
                MessageQueue.GetPublicQueues()

            Return 

        End Sub 'GetAllPublicQueues



        ' Gets a list of all public queues that match  
        ' specified criteria. Displays the list on  
        ' screen. 


        Public Sub GetPublicQueuesByCriteria()

            ' Define criteria to filter the queues. 
            Dim myCriteria As New MessageQueueCriteria()
            myCriteria.CreatedAfter = DateTime.Now.Subtract(New _
                TimeSpan(1, 0, 0, 0))
            myCriteria.ModifiedBefore = DateTime.Now
            myCriteria.MachineName = "."
            myCriteria.Label = "My Queue" 

            ' Get a list of queues with that criteria. 
            Dim QueueList As MessageQueue() = _
                MessageQueue.GetPublicQueues(myCriteria)

            ' Display the paths of the queues in the list. 
            Dim queueItem As MessageQueue
            For Each queueItem In QueueList
                Console.WriteLine(queueItem.Path)
            Next queueItem

            Return 

        End Sub 'GetPublicQueuesByCriteria



        ' Gets a list of private queues on the local  
        ' computer. Displays the list on screen. 


        Public Sub GetPrivateQueues()

            ' Get a list of queues with the specified category. 
            Dim QueueList As MessageQueue() = _
                MessageQueue.GetPrivateQueuesByMachine(".")

            ' Display the paths of the queues in the list. 
            Dim queueItem As MessageQueue
            For Each queueItem In QueueList
                Console.WriteLine(queueItem.Path)
            Next queueItem

            Return 

        End Sub 'GetPrivateQueues

End Class 'MyNewQueue

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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