Power on\off PDA screen - The home of Michael Hudson

Wed

Dec

2008

Power on\off PDA screen

If you want to conserve battery power, but dont want to switch off or suspend your device you can use this code to simply switch off the display!

Namespace PDA
    Public Class Video
        Private Const SETPOWERMANAGEMENT As Int32 = 6147

Declare Function ExtEscapeSet Lib "coredll" Alias "ExtEscape" (ByVal hdc As IntPtr, _
                                                  ByVal nEscape As Int32, _
                                                  ByVal cbInput As Int32, _
                                                  ByVal plszInData As Byte(), _
                                                  ByVal cbOutput As Int32, _
                                                  ByVal lpszOutData As IntPtr) As Int32

Declare Function GetDC Lib "coredll" (ByVal hwnd As IntPtr) As IntPtr

Public Enum VideoPowerState As Integer
            VideoPowerOn = 1
            VideoPowerStandBy
            VideoPowerSuspend
            VideoPowerOff
        End Enum

Public Shared Sub PowerOff()
            Dim hdc As IntPtr = GetDC(IntPtr.Zero)
            Dim vpm() As Byte = {12, 0, 0, 0, 1, 0, 0, 0, VideoPowerState.VideoPowerOff, 0, 0, 0, 0}
            ExtEscapeSet(hdc, SETPOWERMANAGEMENT, 12, vpm, 0, IntPtr.Zero)
        End Sub

Public Shared Sub PowerOn()
            Dim hdc As IntPtr = GetDC(IntPtr.Zero)
            Dim vpm() As Byte = {12, 0, 0, 0, 1, 0, 0, 0, VideoPowerState.VideoPowerOn, 0, 0, 0, 0}
            ExtEscapeSet(hdc, SETPOWERMANAGEMENT, 12, vpm, 0, IntPtr.Zero)
        End Sub
    End Class
End Namespace

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