ASP Alliance Member: MTG

Creating VB6 MTS Components

If you are not alreadt familiar with creating basic COM components, this tutorial is NOT for you. Please read my previous articles for an understanding of this concept.

The following is a template you can use with Visual Basic 6 ONLY - use the template as a basis for developing MTS components.

VB6 MTS Component Template (ActiveX DLL Project):

'**********************************************************************************************
'				 MTS VB6 COM Component Template - by Michael Gonzalez
'**********************************************************************************************
'(1) You must create a reference to the Microsoft Transaction Server Type Library (mtxas.dll).
'    If using Windows 2000, choose the COM+ Services Library (comsvcs.dll) instead.
'(2) Set your ClassModule's MTSTransactionMode property to 2 - RequiresTransaction
'    Note: ONLY use 2 - Requires Transaction if you plan on using the component with an MSDTC-
'    compliant Resource Manager such as MSMQ or SQL Server - OTHERWISE, use 
'    1 - No Transactions
'(3) Make sure your project's Unattended Execution property is checked
'(4) Make sure your project's Component Version Compatibility is set to Binary Compatibility
'**********************************************************************************************
'  ObjectControl implements the interface that is used by MTS when the object is
'   activated and/or deactivated - this happens when you call one of the components's methods
'  The ObjectControl implementation makes use of three procedures:
'   1) ObjectControl_Activate
'   2) ObjectControl_CanBePooled
'   3) ObjectControl_Deactivate
'**********************************************************************************************
Implements ObjectControl

Dim objOC As ObjectContext

Public Sub Something()
    'This is a user-defined procedure/method
    'The ObjectContext Object is returned by GetObjectContext
    
    On Error GoTo Abort
    
    '*******************************************************
    '       Perform whatever you want in this area
    '       Visual Basic 6 stuff goes here
    '       The Something() procedure/method is just
    '       an example - you may use properties and other
    '       methods/procedures as well!
    '*******************************************************
    
Finished:
    objOC.SetComplete
        Exit Sub
Abort:
    objOC.SetAbort
        Err.Raise Err.Number, Err.Source, Err.Description
        Exit Sub
End Sub

Private Sub ObjectControl_Activate()
    'MTS invokes this procedure/method when the component/object is instantiated
    Set objOC = GetObjectContext()
    Exit Sub
End Sub

Private Function ObjectControl_CanBePooled() As Boolean
    'This enables MTS object pooling (not currently supported my MTS 2.0)
    ObjectControl_CanBePooled = True
End Function

Private Sub ObjectControl_Deactivate()
    'MTS invokes this procedure/method right before the component/object is released
    Set objOC = Nothing
    Exit Sub
End Sub

Adding your Component to MTS in Windows NT:

Open the Microsoft Transaction Server Explorer.
Navigate to the Console Root\Microsoft Transaction Server\Computers folder.
Click on the My Computer icon.
If MS DTC is not started, right-click on My Computer and click on Start MS DTC.
Click on the Packages Installed folder.
Right-click on the Packages Installed folder then click on New\Package.
Click on Create an empty package..
Enter the name of the package then click on the Next button.
Click on the This user: radio button.
Enter a username and password that will be used by the MTS package of components.
Click on the Finish button.
Navigate to where your newly created package is and open it.
Click on the Components folder.
Right-click on the Components folder then click on New\Component.
Click on Install New Component(s).
Click on the Add files... button and navigate to where your MTS component is located.
Click on the Finish button.
YOUR DONE!

You can now instantiate your component within an ASP like you would any other component (SET obj = Server.Create("Prog.Class")).

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