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Q174825: FIX: Accessing Image Property of PictureBox Diminishes Resources

Article: Q174825
Product(s): Microsoft Visual Basic for Windows
Version(s): 5.0
Operating System(s): 
Keyword(s): kbVBp kbVBp500bug kbVBp600fix kbGrpDSVB kbDSupport kbControl
Last Modified: 28-JAN-2001

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The information in this article applies to:

- Microsoft Visual Basic Learning Edition for Windows, version 5.0, used with:
   - the operating system: Microsoft Windows 95 
   - the operating system: Microsoft Windows 98 
   - the operating system: Microsoft Windows Millennium Edition 
- Microsoft Visual Basic Professional Edition for Windows, version 5.0, used with:
   - the operating system: Microsoft Windows 95 
   - the operating system: Microsoft Windows 98 
   - the operating system: Microsoft Windows Millennium Edition 
- Microsoft Visual Basic Enterprise Edition for Windows, version 5.0, used with:
   - the operating system: Microsoft Windows 95 
   - the operating system: Microsoft Windows 98 
   - the operating system: Microsoft Windows Millennium Edition 
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SYMPTOMS
========

Using the Image property of a PictureBox control repeatedly diminishes GDI and
System resources on Windows 95, Windows 98, or Windows Me.

RESOLUTION
==========

Use the BitBlt API function to provide the same functionality as the Image
property. The following article in the Microsoft Knowledge Base provides
information about using the BitBlt API function:

  Q147810 : HOWTO: Use Windows BitBlt Function in Visual Basic Application

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article. This bug has been fixed in Visual Basic 6.0.

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

The following shows you how to create a sample project that demonstrates this
bug. The instructions assume that you have the System Resource Meter running so
you can see the effect of accessing the Image property. The System Resource
Meter is a system tool usually installed in the Accessories program group if you
select the System Resource Meter option when you install Windows 95 or Windows
98.

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

1. Start a new Standard EXE project in Visual Basic. Form1 is created by
  default.

2. Add a PictureBox, Command Button, and Label control to Form1.

3. Set the Picture property of the PictureBox control to an appropriate bitmap
  file.

4. Copy the following code to the Code window of Form1:

        Option Explicit
        Private Sub Command1_Click()
           Dim I as Integer
           For I = 1 to 100
              Picture1.Picture = Picture1.Image
              Label1.Caption = Trim(Str(I))
              DoEvents
           Next I
        End Sub

5. Press the F5 key to run the program. Minimize the Visual Basic IDE so you can
  see both Form1 and the System Resource meter running. Click Command1 and note
  that the GDI and System Resources diminish by about 20 percent with the click
  of the CommandButton.

Additional query words: memory leak resource

======================================================================
Keywords          : kbVBp kbVBp500bug kbVBp600fix kbGrpDSVB kbDSupport kbControl 
Technology        : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2
Version           : :5.0
Issue type        : kbbug
Solution Type     : kbfix

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