VB3 Start a Visual Basic Screen Saver Using SendMessage API

 Last reviewed: January 9, 1997
Article ID: Q110589
The information in this article applies to:
  • Standard and Professional Editions of Microsoft Visual Basic for Windows, version 3.0

SUMMARY

The sample code below shows how to start a Visual Basic screen saver by sending a Windows message to the Control-menu box on the form.

MORE INFORMATION

Microsoft Windows starts screen savers through the System-menu box on a form. The System-menu box is also known as the Control-menu box in Visual Basic. You can send Windows messages to the Control-menu box by using the SendMessage Windows API (application programming interface) function.

Add the following to the general declarations section of Form1, or to a .Bas module file, in Visual Basic: 

   ' The following Declare statement must be on one, single line:
   Declare Function SendMessage Lib "User" (ByVal hWnd As Integer,
      ByVal wMsg As Integer, ByVal wParam As Integer, lParam As Any) As
      Long
In the following example, a command button starts the Form1 screen saver: 

   Sub Command1_Click ()
      Dim result As Long
      Const WM_SYSCOMMAND = &H112
      Const SC_SCREENSAVE = &HF140
      result = SendMessage(Form1.hWnd, WM_SYSCOMMAND, SC_SCREENSAVE, 0&)
   End Sub
You can find two sample programs and a complete explanation showing how to write your own screen savers in Visual Basic in the following book: 

   "Visual Basic Workshop 3.0" by John C. Craig, published by Microsoft
   Press.

KBCategory: kbprg kbcode
KBSubcategory: PrgCtrlsStd
Additional reference words: 3.00 .SCR TOPMOST SETWINDOWPOS SCRNSAVE timer

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Last reviewed: January 9, 1997
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