Search
Module:
Directory

   Desktop Functions:

   Smart Device Functions:


Show Recent Changes
Subscribe (RSS)
Misc. Pages
Comments
FAQ
Helpful Tools
Playground
Suggested Reading
Website TODO List
Download Visual Studio Add-In

registerpowersettingnotification (user32)
 
.
Summary
Enables your app to receive the WM_POWERBROADCAST window message, which notifies applications about power management events

C# Signature:

    [DllImport(@"User32", SetLastError=true, EntryPoint = "RegisterPowerSettingNotification",
         CallingConvention = CallingConvention.StdCall)]
    private static extern IntPtr RegisterPowerSettingNotification(
        IntPtr hRecipient,
        ref Guid PowerSettingGuid,
        Int32 Flags);

VB Signature:

Declare Function RegisterPowerSettingNotification Lib "user32.dll" (TODO) As TODO

User-Defined Types:

       private const int WM_POWERBROADCAST = 0x0218;

    static Guid GUID_BATTERY_PERCENTAGE_REMAINING = new Guid("A7AD8041-B45A-4CAE-87A3-EECBB468A9E1");
    static Guid GUID_MONITOR_POWER_ON = new Guid(0x02731015, 0x4510, 0x4526, 0x99, 0xE6, 0xE5, 0xA1, 0x7E, 0xBD, 0x1A, 0xEA);
    static Guid GUID_ACDC_POWER_SOURCE = new Guid(0x5D3E9A59, 0xE9D5, 0x4B00, 0xA6, 0xBD, 0xFF, 0x34, 0xFF, 0x51, 0x65, 0x48);
    static Guid GUID_POWERSCHEME_PERSONALITY = new Guid(0x245D8541, 0x3943, 0x4422, 0xB0, 0x25, 0x13, 0xA7, 0x84, 0xF6, 0x79, 0xB7);
    static Guid GUID_MAX_POWER_SAVINGS = new Guid(0xA1841308, 0x3541, 0x4FAB, 0xBC, 0x81, 0xF7, 0x15, 0x56, 0xF2, 0x0B, 0x4A);
    // No Power Savings - Almost no power savings measures are used.
    static Guid GUID_MIN_POWER_SAVINGS = new Guid(0x8C5E7FDA, 0xE8BF, 0x4A96, 0x9A, 0x85, 0xA6, 0xE2, 0x3A, 0x8C, 0x63, 0x5C);
    // Typical Power Savings - Fairly aggressive power savings measures are used.
    static Guid GUID_TYPICAL_POWER_SAVINGS = new Guid(0x381B4222, 0xF694, 0x41F0, 0x96, 0x85, 0xFF, 0x5B, 0xB2, 0x60, 0xDF, 0x2E);

    // Win32 decls and defs
    //
    const int PBT_APMQUERYSUSPEND = 0x0000;
    const int PBT_APMQUERYSTANDBY = 0x0001;
    const int PBT_APMQUERYSUSPENDFAILED = 0x0002;
    const int PBT_APMQUERYSTANDBYFAILED = 0x0003;
    const int PBT_APMSUSPEND = 0x0004;
    const int PBT_APMSTANDBY = 0x0005;
    const int PBT_APMRESUMECRITICAL = 0x0006;
    const int PBT_APMRESUMESUSPEND = 0x0007;
    const int PBT_APMRESUMESTANDBY = 0x0008;
    const int PBT_APMBATTERYLOW = 0x0009;
    const int PBT_APMPOWERSTATUSCHANGE = 0x000A; // power status
    const int PBT_APMOEMEVENT = 0x000B;
    const int PBT_APMRESUMEAUTOMATIC = 0x0012;
    const int PBT_POWERSETTINGCHANGE = 0x8013; // DPPE

    const int DEVICE_NOTIFY_WINDOW_HANDLE = 0x00000000;
    const int DEVICE_NOTIFY_SERVICE_HANDLE = 0x00000001;

    // This structure is sent when the PBT_POWERSETTINGSCHANGE message is sent.
    // It describes the power setting that has changed and contains data about the change
    [StructLayout(LayoutKind.Sequential, Pack = 4)]
    internal struct POWERBROADCAST_SETTING
    {
        public Guid PowerSetting;
        public Int32 DataLength;
    }

Alternative Managed API:

Do you know one? Please contribute it!

Notes:

New for Windows Vista

Tips & Tricks:

Please add some!

Sample Code:

private void RegisterForPowerNotifications(IntPtr hwnd)

    {
        hPowerSrc = RegisterPowerSettingNotification(hwnd,
        ref GUID_ACDC_POWER_SOURCE,
        DEVICE_NOTIFY_WINDOW_HANDLE);

        hBattCapacity = RegisterPowerSettingNotification(hwnd,
        ref GUID_BATTERY_PERCENTAGE_REMAINING,
        DEVICE_NOTIFY_WINDOW_HANDLE);

        hMonitorOn = RegisterPowerSettingNotification(hwnd,
        ref GUID_MONITOR_POWER_ON,
        DEVICE_NOTIFY_WINDOW_HANDLE);

        hPowerScheme = RegisterPowerSettingNotification(hwnd,
        ref GUID_POWERSCHEME_PERSONALITY,
        DEVICE_NOTIFY_WINDOW_HANDLE);
    }

private static IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)

    {
        if (msg == WM_POWERBROADCAST && wParam.ToInt32() == PBT_POWERSETTINGCHANGE)
        {
        // Extract data from message
        POWERBROADCAST_SETTING ps =
         (POWERBROADCAST_SETTING)Marshal.PtrToStructure(
             lParam, typeof(POWERBROADCAST_SETTING));
        IntPtr pData = (IntPtr)(lParam.ToInt32() + Marshal.SizeOf(ps));

        // Examine notification

        if (ps.PowerSetting == GUID_POWERSCHEME_PERSONALITY &&
            ps.DataLength == Marshal.SizeOf(typeof(Guid)))
        {
            // New power scheme selected.

            Guid newPersonality =
            (Guid)Marshal.PtrToStructure(pData, typeof(Guid));

            if (newPersonality == GUID_MAX_POWER_SAVINGS)
            {
            personality = PowerPersonality.Savings;
            }
            else if (newPersonality == GUID_MIN_POWER_SAVINGS)
            {
            personality = PowerPersonality.Performance;
            }
            else if (newPersonality == GUID_TYPICAL_POWER_SAVINGS)
            {
            personality = PowerPersonality.Mixed;
            }
            else
            {
            Debug.WriteLine("switched to unknown Power savings");
            personality = PowerPersonality.Mixed;
            }
        }
        else if (ps.PowerSetting == GUID_ACDC_POWER_SOURCE &&
             ps.DataLength == Marshal.SizeOf(typeof(Int32)))
        {
            Int32 iData = (Int32)Marshal.PtrToStructure(pData, typeof(Int32));
            Debug.WriteLine("ACDC: " + iData);

            onBattery = iData != 0;
        }

Documentation
[RegisterPowerSettingNotification]://windowssdk.msdn.microsoft.com/en-us/library/ms703398(VS.80).aspx on MSDN

Please edit this page!

Do you have...

  • helpful tips or sample code to share for using this API in managed code?
  • corrections to the existing content?
  • variations of the signature you want to share?
  • additional languages you want to include?

Select "Edit This Page" on the right hand toolbar and edit it! Or add new pages containing supporting types needed for this API (structures, delegates, and more).

 
Access PInvoke.net directly from VS:
Terms of Use
Find References
Show Printable Version
Revisions