How to Start a Visual Basic Screen Saver Using SendMessage API

• Microsoft Visual Basic Standard, Professional, and Enterprise Editions, 16-bit 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 query words: 3.00 4.00 vb4win vb4all .SCR TOPMOST SETWINDOWPOS SCRNSAVE
timer

Keywords : kbcode PrgCtrlsStd
Version : 4.00
Platform : WINDOWS
Issue type :