FIX: Accessing Image Property of PictureBox Diminishes Resources

• Microsoft Visual Basic Learning, Professional, and Enterprise Editions for Windows, version 5.0, on platform(s):
  • Windows 98

SYMPTOMS

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

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 leak kbVBp500bug kbVBp kbDSupport kbdsd
kbVBp600fix kbControl

Keywords : kbGrpVB
Version :
Platform : Win95 WINDOWS Win98
Issue type : kbbug