How to Start a Visual Basic Screen Saver Using SendMessage API (141024)


The information in this article applies to:

  • Microsoft Visual Basic Standard Edition, 32-bit, for Windows 4.0
  • Microsoft Visual Basic Professional Edition, 16-bit, for Windows 4.0
  • Microsoft Visual Basic Professional Edition, 32-bit, for Windows 4.0
  • Microsoft Visual Basic Enterprise Edition, 16-bit, for Windows 4.0
  • Microsoft Visual Basic Enterprise Edition, 32-bit, for Windows 4.0
This article was previously published under Q141024

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.
Modification Type:MajorLast Reviewed:12/9/2003
Keywords:kbcode KB141024
©2003 Microsoft Corporation. All rights reserved.