pinvoke.net: Edit: user32.RegisterPowerSettingNotification

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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 uint DataLength;
            public byte Data;
        }

!!!!Alternative Managed API:
Do you know one?  Please contribute it!

!!!!Notes:
New for Windows Vista

!!!!Tips & Tricks:
Please add some!

!!!!Sample Code:

A full sample application can be downloaded from Microsoft:
http://www.microsoft.com/downloads/details.aspx?FamilyID=c6f140ce-3dfb-49c4-b365-2a79e799817a&displaylang=en

Recommended reading:
http://msdn.microsoft.com/en-us/magazine/cc163417.aspx

[StructLayout(LayoutKind.Sequential, Pack = 4)]
        internal struct POWERBROADCAST_SETTING {
            public Guid PowerSetting;
            public uint DataLength;
            // public byte Data;    // (*1)
        }

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));  // (*1)

// 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@http://windowssdk.msdn.microsoft.com/en-us/library/ms703398(VS.80).aspx on MSDN