// Establish a Request filter opportunistic lock
private static IAsyncResult BeginFilter(AsyncCallback asyncCallback, Object state)
{
// See FSCTL_REQUEST_FILTER_OPLOCK in Platform SDK's WinIoCtl.h file
DeviceControlCode RequestFilterOpLock =
new DeviceControlCode(DeviceType.FileSystem, 23, DeviceMethod.Buffered, DeviceAccess.Any);
return m_device.BeginControl(RequestFilterOpLock, null, asyncCallback, state);
}
public static extern bool DeviceIoControl(SafeFileHandle driveHandle
, DeviceControlCode ioControlCode
, IntPtr lpInBuffer
, uint inBufferSize
, SafeHandle lpOutBuffer
, uint outBufferSize
, ref uint lpBytesReturned
, IntPtr lpOverlapped);
public static extern bool DeviceIoControl(
[In] SafeFileHandle hDevice,
[In][MarshalAs(UnmanagedType.U4)] DeviceControlCode dwIoControlCode,
[In, Optional][MarshalAs(UnmanagedType.LPArray)] byte[] lpInBuffer,
[In][MarshalAs(UnmanagedType.U4)] uint nInBufferSize,
[Out, Optional][MarshalAs(UnmanagedType.LPArray)] byte[] lpOutBuffer,
[In][MarshalAs(UnmanagedType.U4)] uint nOutBufferSize,
[Out, Optional][MarshalAs(UnmanagedType.U4)] out uint lpBytesReturned,
[In, Out, Optional] IntPtr lpOverlapped);
internal static Tuple <T, byte[]> DeviceIoControlAction <T, U>(SafeFileHandle safeHandle, DeviceControlCode controlCode, U input, int outputSize = Win32Constants.SIZE_OUTPUT) where T : struct where U : struct
{
var inputSize = Marshal.SizeOf(input);
var inputPtr = Marshal.AllocHGlobal(inputSize);
Marshal.StructureToPtr(input, inputPtr, false);
byte[] inputBuffer = new byte[inputSize];
byte[] outputBuffer = new byte[outputSize];
Marshal.Copy(inputPtr, inputBuffer, 0, inputSize);
Marshal.FreeHGlobal(inputPtr);
if (!NativeMethods.DeviceIoControl(
safeHandle,
controlCode,
inputBuffer,
(uint)inputBuffer.Length,
outputBuffer,
(uint)outputBuffer.Length,
out uint bytesReturned,
IntPtr.Zero))
{
Marshal.ThrowExceptionForHR(Marshal.GetHRForLastWin32Error());
}
var outputPtr = Marshal.AllocHGlobal(outputBuffer.Length);
Marshal.Copy(outputBuffer, 0, outputPtr, outputBuffer.Length);
T result = Marshal.PtrToStructure <T>(outputPtr);
Marshal.FreeHGlobal(outputPtr);
return(new Tuple <T, byte[]>(result, outputBuffer));
}
private static void LCDBrightnessForMsdnMagazine()
{
DeviceControlCode s_SetBrightness =
new DeviceControlCode(DeviceType.Video, 0x127, DeviceMethod.Buffered, DeviceAccess.Any);
using (DeviceIO lcd = new DeviceIO(@"\\.\LCD", FileAccess.ReadWrite, FileShare.ReadWrite, false)) {
for (Int32 times = 0; times < 10; times++) {
for (Int32 dim = 0; dim <= 100; dim += 20) {
Win32DisplayBrightnessStructure db = new Win32DisplayBrightnessStructure(Win32DisplayBrightnessStructure.DisplayPowerFlags.ACDC,
(Byte)((times % 2 == 0) ? dim : 100 - dim));
lcd.Control(s_SetBrightness, db);
Thread.Sleep(150);
}
}
}
}
