Posts Tagged ‘SC_MONITORPOWER’

Here is another good tip which you may find helpfull.

Lets say you want to control the Monitor’s power state (On/Standby) via VB.

In my case, my Den holds my wife’s and my computer.  The program already (using the before mentioned X10 sensors) detects movement after sunset it will ‘talk’ the weather of two zip codes (Home and work) but I would like it also to ‘bring’ back the computer from its monitor power saving mode, so even before I touch the mouse, the computer is waiting for me.
Basically the code does is calls directly to the User32 library (like to good old VB6 days).    In case we will alter the SC_MONITORPOWER state from -1, to 0, and calling other System values in HEX.

Below is how its done in VB 2005 / .NET,
Here
is the same thing but in “C” code, I basically converted it from here.

Steps,

1st we will define the Function that will be called,

2nd We will define 2 subroutines or functions that we can call I called them “WakeUp” and “Sleep.

Again this only consist of the monitor ‘power’ state, the computer is not on standby or hibernation. Many of today’s computer now have WOL capability BUT only for wired (Cat 5) connections, in my case I use USB wireless all around the house and I haven’t gotten that part to work yet.

Code below,

Public Class Form1

    '-------------- FUNCTION TO WAKE UP SCREEN
    Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hWnd As IntPtr, ByVal wMsg As Integer, ByVal wParam As Integer, ByVal lParam As Integer) As Integer

    Dim WM_SYSCOMMAND As Integer = &H112
    Dim SC_MONITORPOWER As Integer = &HF170
    Dim HWND_BROADCAST As Integer = &HFFFF

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

                 ... all your startup code here...




 Public Sub Wakeup()

        Beep() '---- Just for fun
        SendMessage(HWND_BROADCAST, WM_SYSCOMMAND, SC_MONITORPOWER, -1)
    End Sub

    Public Sub Sleep()
        SendMessage(HWND_BROADCAST, WM_SYSCOMMAND, SC_MONITORPOWER, 2)
    End Sub



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