Q257645: FIX: Setting Windowless Control to Transparent Prevents Animatio

Article: Q257645
Product(s): Microsoft Visual Basic for Windows
Version(s): WINDOWS:6.0
Operating System(s): 
Keyword(s): kbCtrlCreate kbVBp kbVBp600bug kbGrpDSVB kbDSupport kbVS600sp4fix kbVS600sp5fix
Last Modified: 27-JUL-2001

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The information in this article applies to:

- Microsoft Visual Basic Professional Edition for Windows, version 6.0 
- Microsoft Visual Basic Enterprise Edition for Windows, version 6.0 
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SYMPTOMS
========

When you set the BackStyle property of a windowless control to Transparent,
animation effects for that control are prevented from taking place. The effects
are drawn, but they are not animated.

CAUSE
=====

This behavior is due to the way Visual Basic draws controls.

STATUS
======

Microsoft has confirmed that this is a bug in the Microsoft products that are
listed at the beginning of this article. This bug was corrected in the latest
service pack for Visual Studio 6.0.

For additional information about Visual Studio service packs, click the following
article numbers to view the articles in the Microsoft Knowledge Base:

  Q194022 INFO: Visual Studio 6.0 Service Packs, What, Where, Why

  Q194295 HOWTO: Tell That a Visual Studio Service Pack Is Installed

To download the latest Visual Studio service pack, visit the following Microsoft
Web site:

  http://msdn.microsoft.com/vstudio/downloads/updates.asp

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

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

1. Create a new ActiveX Control project in Visual Basic. UserControl1 is created
  by default.

2. Change the Height and Width property of UserControl1 to 1680.

3. Change the Windowless property of UserControl1 to True.

4. Add the following code to UserControl1:

  Option Explicit

  Private x As Long
  Private y As Long

  Public Property Get BackStyle() As Integer
      BackStyle = UserControl.BackStyle
  End Property

  Public Property Let BackStyle(ByVal New_BackStyle As Integer)
      UserControl.BackStyle() = New_BackStyle
      PropertyChanged "BackStyle"
  End Property

  Public Property Get BackColor() As OLE_COLOR
      BackColor = UserControl.BackColor
  End Property

  Public Property Let BackColor(ByVal New_BackColor As OLE_COLOR)
      UserControl.BackColor() = New_BackColor
      PropertyChanged "BackColor"
  End Property

  Private Sub UserControl_Initialize()
      x = Width
      y = x
  End Sub

  Private Sub UserControl_Paint()
      If Ambient.UserMode = False Then Exit Sub
      Randomize
      Dim i As Integer
      Dim j As Integer
      For j = 1 To 40
          For i = 1 To 30000
              If i Mod 10000 = 0 Then
                  Circle (x * Rnd, y * Rnd), 50
              End If
          Next
      Next
  End Sub

  ' Load property values from storage
  Private Sub UserControl_ReadProperties(PropBag As PropertyBag)

      UserControl.BackStyle = PropBag.ReadProperty("BackStyle", 1)
      UserControl.BackColor = PropBag.ReadProperty("BackColor", &H8000000F)
  End Sub

  ' Write property values to storage
  Private Sub UserControl_WriteProperties(PropBag As PropertyBag)

      Call PropBag.WriteProperty("BackStyle", UserControl.BackStyle, 1)
      Call PropBag.WriteProperty("BackColor", UserControl.BackColor, &H8000000F)
  End Sub

5. From the File menu, select Add Project. Choose Standard EXE and click Open.
  Form1 is created by default.

6. Close the (designer) window for UserControl1.

7. Add two instances of UserControl1 to Form1. They are named UserControl11 and
  UserControl12.

8. Change the BackColor property of both UserControls to something other than
  grey.

9. In the Project Explorer, change the startup project by right-clicking on
  Project2. Select Set as Startup.

10. Press the F5 key to run the project. Note that you can see circles being
  drawn on the controls (animation.)

11. Stop the project and change the BackStyle property of UserControl12 to 0
  (Transparent.)

12. Press F5 to run, and note that you do not see the circle animation on
  UserControl11. The form becomes transparent while animating, but you only
  see the circles on the control after the animation has taken place.

REFERENCES
==========

For additional information on Windowless controls, click the article number
below to view the article in the Microsoft Knowledge Base:

  Q184645 HOWTO: Create Lightweight Controls with Visual Basic 6.0

Additional query words: sp4

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Keywords          : kbCtrlCreate kbVBp kbVBp600bug kbGrpDSVB kbDSupport kbVS600sp4fix kbVS600sp5fix 
Technology        : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB600Search kbVB600
Version           : WINDOWS:6.0
Issue type        : kbbug
Solution Type     : kbfix

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