Sdílet prostřednictvím

Visual Basic Code Example: Reading Report Messages

  • Článek

 

Applies To: Windows 10, Windows 7, Windows 8, Windows 8.1, Windows Server 2008, Windows Server 2008 R2, Windows Server 2012, Windows Server 2012 R2, Windows Server Technical Preview, Windows Vista

This example provides an application-defined Sub procedure that synchronously reads each message in a report queue, peeking at the MSMQMessage.MsgClass property and displaying the label of each report message that is in the report queue.

For information on tracing the route of a message, see Tracing Messages.

To read report messages

  1. Declare the objects needed to read the messages in the queue:

  2. Obtain an MSMQQueueInfo object. The following example initializes the MSMQQueueInfo object by setting the MSMQQueueInfo.PathName property using the computer name and queue name provided by the caller.

  3. Because this procedure sets the MSMQQueueInfo.PathName property of the MSMQQueueInfo object, Message Queuing must obtain the format name of the queue before opening the queue. The format name of a public queue must be retrieved from the directory service, and the format name of a local private queue can be obtained from information stored on the local computer. However, a remote private queue cannot be opened unless the MSMQQueueInfo.FormatName property is set with a direct format name. This procedure can be modified to receive the format name from the caller or to generate a direct format name. The applicable format name can then be used to set the FormatName property. For more information, see Format Names.

  4. Call MSMQQueueInfo.Open to open the queue with receive access. When opening a queue with receive access the application can peek at or retrieve the messages in the queue.

  5. Call MSMQQueue.PeekCurrent to initialize the cursor. This call points the cursor to the first message in the queue.

  6. Using a loop, display the label of each report message in the queue.

  7. When there are no messages left, call MSMQQueue.Close to release resources used to open queue and exit the Sub procedure.

Code Example

The following code example requires MSMQ 2.0 or later.

Private Sub ReadMassagesInReportQueue( _  
                                      strComputerName As String, _  
                                      strReportQueuename As String _  
                                      )  
  ' Declare Message Queuing objects.  
  Dim qinfo As New MSMQQueueInfo  
  Dim q As MSMQQueue  
  Dim msg As MSMQMessage  
  
  ' Set the path name in the MSMQQueueInfo object.  
  qinfo.PathName = strComputerName & "\" & strReportQueuename  
  On Error GoTo ErrorHandler  
  
  ' Open the report queue with receive access.  
  Set q = qinfo.Open(Access:=MQ_RECEIVE_ACCESS, ShareMode:=MQ_DENY_NONE)  
  
  ' Initialize the cursor.  
  Set msg = q.PeekCurrent(ReceiveTimeout:=1000)  
  
  ' Peek at messages in the queue using the cursor.  
  Do While Not msg Is Nothing  
  
    ' If the message is a report message, print the label.  
    If msg.MsgClass = MQMSG_CLASS_REPORT Then  
      MsgBox msg.Label  
     End If  
     Set msg = q.PeekNext(ReceiveTimeout:=1000)  
  Loop  
  
  ' Close the queue.  
  q.Close  
  Exit Sub  
  
ErrorHandler:  
  MsgBox "Error " + Hex(Err.Number) + " was returned. " + Chr(13) + _  
         "Description: " + Err.Description  
  If Not q Is Nothing And q.IsOpen2 Then  
    q.Close  
  EndIf  
End Sub