How to Start a Visual Basic Screen Saver Using SendMessage API

 Last reviewed: September 6, 1996
Article ID: Q141024
The information in this article applies to:
  • Standard, Professional, and Enterprise Editions of Microsoft Visual Basic, 16 and 32 bit, for Windows, version 4.0

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 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 reference words: 3.00 4.00 vb4win vb4all .SCR TOPMOST
SETWINDOWPOS SCRNSAVE timer
KBCategory: kbprg kbcode
KBSubcategory: PrgCtrlsStd

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Last reviewed: September 6, 1996
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