WPF改变亮度

[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]

static extern bool GetDevicePowerState(int deviceNumber, ref DEVICE_POWER_STATE powerState);

[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]

static extern bool SetDevicePowerState(int deviceNumber, DEVICE_POWER_STATE powerState);

private const int SM_TABLETPC = 86;

private const int SM_MEDIACENTER = 87;

private const int SM_STARTER = 88;

private const int SM_SERVERR2 = 89;

private const int SM_MOBILE = 90;

private const int SPI_GETSCREENSAVERRUNNING = 114;

private const int SPI_SETSCREENSAVERRUNNING = 115;

private const int SPI_GETSCREENSAVEACTIVE = 16;

private const int SPI_SETSCREENSAVEACTIVE = 17;

private const int SPI_GETSCREENSAVETIMEOUT = 14;

private const int SPI_SETSCREENSAVETIMEOUT = 15;

private const int SPI_GETLOWPOWERACTIVE = 83;

private const int SPI_SETLOWPOWERACTIVE = 84;

private const int SPI_GETPOWEROFFACTIVE = 85;

private const int SPI_SETPOWEROFFACTIVE = 86;

private const int SPI_GETSCREENSAVESECURE = 77;

private const int SPI_SETSCREENSAVESECURE = 78;

private const int SPI_GETACTIVEWINDOWTRACKING = 47;

private const int SPI_SETACTIVEWINDOWTRACKING = 48;

private const int SPI_GETMENUANIMATION = 42;

private const int SPI_SETMENUANIMATION = 43;

private const int SPI_GETCOMBOBOXANIMATION = 9;

private const int SPI_SETCOMBOBOXANIMATION = 10;

private const int SPI_GETLISTBOXSMOOTHSCROLLING = 52;

private const int SPI_SETLISTBOXSMOOTHSCROLLING = 53;

private const int SPI_GETGRADIENTCAPTIONS = 69;

private const int SPI_SETGRADIENTCAPTIONS = 70;

private const int SPI_GETKEYBOARDCUES = 44;

private const int SPI_SETKEYBOARDCUES = 45;

private const int SPI_GETMENUUNDERLINES = 74;

private const int SPI_SETMENUUNDERLINES = 75;

private const int SPI_GETACTIVEWNDTRKZORDER = 54;

private const int SPI_SETACTIVEWNDTRKZORDER = 55;

private const int SPI_GETHOTTRACKING = 76;

private const int SPI_SETHOTTRACKING = 77;

private const int SPI_GETFOREGROUNDLOCKTIMEOUT = 81;

private const int SPI_SETFOREGROUNDLOCKTIMEOUT = 82;

private const int SPI_GETACTIVEWNDTRKTIMEOUT = 8;

private const int SPI_SETACTIVEWNDTRKTIMEOUT = 9;

private const int SPI_GETFOREGROUNDFLASHCOUNT = 20;

private const int SPI_SETFOREGROUNDFLASHCOUNT = 21;

private const int SPI_GETCARETWIDTH = 41;

private const int SPI_SETCARETWIDTH = 42;

private const int SPI_GETMOUSECLICKLOCK = 82;

private const int SPI_SETMOUSECLICKLOCK = 83;

private const int SPI_GETFONTSMOOTHINGTYPE = 74;

private const int SPI_SETFONTSMOOTHINGTYPE = 75;

private const int SPI_GETFONTSMOOTHINGCONTRAST = 72;

private const int SPI_SETFONTSMOOTHINGCONTRAST = 73;

private const int SPI_GETFOCUSBORDERWIDTH = 84;

private const int SPI_SETFOCUSBORDERWIDTH = 85;

private const int SPI_GETFOCUSBORDERHEIGHT = 86;

private const int SPI_SETFOCUSBORDERHEIGHT = 87;

private const int SPI_GETFONTSMOOTHINGORIENTATION = 76;

private const int SPI_SETFONTSMOOTHINGORIENTATION = 77;

public enum DEVICE_POWER_STATE

{

    PowerDeviceUnspecified = 0,

    PowerDeviceD0,

    PowerDeviceD1,

    PowerDeviceD2,

    PowerDeviceD3,

    PowerDeviceMaximum

}

public enum