DOCUMENT:Q193025  23-SEP-1998  [vbwin]
TITLE   :BUG: Cannot Dynamically Add a Non-Licensed MFC Control
PRODUCT :Microsoft Visual Basic for Windows
PROD/VER:WINDOWS:6.0
OPER/SYS:WINDOWS
KEYWORDS:

======================================================================
---------------------------------------------------------------------
The information in this article applies to:

 - Microsoft Visual Basic Learning, Professional, and Enterprise Editions
   for Windows, version 6.0
---------------------------------------------------------------------

SYMPTOMS
========

When attempting to dynamically add an MFC ActiveX control to a Visual Basic
project, you may receive the following error message in the compiled
project:

   Run-time error '747':

   No design-time license information is found for control 'XX.YY'. Contact
   the vendor for control 'XX.YY' to obtain a design-time license.

The error occurs even though the control does not require a license.

CAUSE
=====

When adding a new control to a Form or UserControl dynamically at run-time,
Visual Basic queries the control for the IClassFactory2 interface. This
interface is generally used by controls that require licensing. If the
control supports this interface, Visual Basic will then attempt to create
an instance of the control using the IClassFactory2::CreateInstanceLic
method, passing the developer-provided license string as a parameter. If no
license is required, an empty string is passed.

By default, all MFC ActiveX controls support the IClassFactory2 interface,
even if the control does not require a design-time license. When Visual
Basic makes the call to CreateInstanceLic, passing an empty string for the
license, MFC returns the error CLASS_E_NOTLICENSED, indicating that the
string passed is not a valid license key for this control. Visual Basic
reports the error as an invalid or missing design-time license.

RESOLUTION
==========

There are currently two workarounds for this problem:

1. If you add the MFC control to the Visual Basic IDE toolbox at
   design-time, and then uncheck the "Remove information about unused
   ActiveX controls" option on the Make tab of the Project|Properties
   dialog, Visual Basic will compile the licensing information of the
   control into your project. At run-time, Visual Basic will know that the
   control does not require a license, and therefore will call
   CreateInstance rather than CreateInstanceLic. This will avoid the error.

2. You can site the MFC control on a Visual Basic ActiveX control, expose
   its properties and methods, and then dynamically add the Visual Basic
   control at run-time.

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed
at the beginning of this article.

MORE INFORMATION
================

Steps to Reproduce Behavior
---------------------------

1. Start Visual C++. Create a new project and select MFC ActiveX Control
   Wizard. Name the project MFCTest.

2. From the Wizard Dialog, make sure the option "No run-time license" is
   selected and then click Next. From the "Which window class should this
   control subclass" drop-down box, select BUTTON. Then click Finish.

3. Build the MFC control by pressing the F7 key. The control will be
   registered on the system for you.

4. Open Visual Basic 6.0 and start a Standard EXE project. Form1 is created
   by default.

5. In the code window for Form1, add the following:

      Private m_MFCCtrl As VBControlExtender

      Private Sub Form_Load()
         Set m_MFCCtrl = Controls.Add("MFCTest.MFCTestCtrl.1", "xx", Me)
         m_MFCCtrl.Visible = True
      End Sub

   NOTE: If you chose a different name than "MFCTest" for your MFC project,
   you may need to change the ProgID passed to the Controls.Add method.

6. Run the project once to see that Visual Basic can dynamically add the
   MFC control while debugging in the IDE.

7. Compile the Visual Basic project and run the compiled executable. You
   should receive the run-time error '747' on Form load.

8. To avoid the error, add your MFC control to the IDE toolbox before you
   compile the project. Click Components on the Project menu and check
   "MFCTest ActiveX control module" from the Components list. Click OK.

9. To make sure Visual Basic doesn't remove unused references at compile-
   time, select Project1 Properties from the Project menu and click the
   Make tab. Uncheck the "Remove information about unused ActiveX controls"
   option and then press OK.

10. Re-compile the project and run the compiled executable. The error
   should no longer occur.

REFERENCES
==========

For additional information, please see the following articles in the
Microsoft Knowledge Base:

   ARTICLE-ID: Q190670
   TITLE     : HOWTO: Dynamically Add Controls to a Form with Visual
               Basic 6.0

   ARTICLE-ID: Q188577
   TITLE     : HOWTO: What is the Licenses Collection Used For?

Additional query words: kbDSupport kbDSD kbVBp kbVBp600bug kbCtrlCreate
kbActiveX kbVC
======================================================================
Version           : WINDOWS:6.0
Platform          : WINDOWS
Issue type        : kbbug

=============================================================================

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