DOCUMENT:Q141024  20-FEB-2002  [vbwin]
TITLE   :How to Start a Visual Basic Screen Saver Using SendMessage API
PRODUCT :Microsoft Visual Basic for Windows
PROD/VER::4.0
OPER/SYS:
KEYWORDS:kbcode

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The information in this article applies to:

 - Microsoft Visual Basic Standard Edition, 32-bit, for Windows, version 4.0 
 - Microsoft Visual Basic Professional Edition, 16-bit, for Windows, version 4.0 
 - Microsoft Visual Basic Professional Edition, 32-bit, for Windows, version 4.0 
 - Microsoft Visual Basic Enterprise Edition, 16-bit, for Windows, version 4.0 
 - Microsoft Visual Basic Enterprise Edition, 32-bit, for Windows, version 4.0 
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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 a 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.

   [general declarations]
   #If Win32 Then
       Private Declare Function SendMessage Lib "user32" Alias _
   "SendMessageA" (ByVal hWnd As Long, ByVal wMsg As Long, _     ByVal wParam
   As Long, ByVal lParam As Long) As Long
       Const WM_SYSCOMMAND = &H112&
       Const SC_SCREENSAVE = &HF140&
   #Else
       Private Declare Function SendMessage Lib "User" (ByVal _         hWnd
   As Integer, ByVal wMsg As Integer, ByVal wParam As _             Integer,
   lParam As Any) As Long
       Const WM_SYSCOMMAND = &H112
       Const SC_SCREENSAVE = &HF140&
   #End If

   Private Sub Command1_Click()
       Dim result As Long
       result = SendMessage(Form1.hWnd, WM_SYSCOMMAND, _
        SC_SCREENSAVE, 0&)
   End Sub

REFERENCES
==========

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.

Additional query words: 3.00 4.00 vb4win vb4all .SCR TOPMOST SETWINDOWPOS SCRNSAVE timer

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Keywords          : kbcode 
Technology        : kbVBSearch kbAudDeveloper kbVB400Search kbVB400 kbVB16bitSearch
Version           : :4.0

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