C# Signature:

[DllImport("kernel32.dll", ExactSpelling = true, SetLastError = true, CharSet = CharSet.Auto)]
static extern bool DeviceIoControl(IntPtr hDevice, uint dwIoControlCode,
IntPtr lpInBuffer, uint nInBufferSize,
IntPtr lpOutBuffer, uint nOutBufferSize,
out uint lpBytesReturned, IntPtr lpOverlapped);

C# Signature:

[DllImport("Kernel32.dll", CharSet=CharSet.Auto, SetLastError=true)]
public static extern bool DeviceIoControl( IntPtr hDevice, uint dwIoControlCode, ref long InBuffer,
int nInBufferSize, ref long OutBuffer, int nOutBufferSize,
ref int pBytesReturned, [In] ref NativeOverlapped lpOverlapped);

VB Signature:

<DllImport("kernel32.dll", ExactSpelling:=True, SetLastError:=True, CharSet:=CharSet.Auto)> _
   Private Shared Function DeviceIoControl(ByVal hDevice As IntPtr, _
     ByVal dwIoControlCode As Int32, ByVal lpInBuffer As IntPtr, _
     ByVal nInBufferSize As Int32, ByVal lpOutBuffer As IntPtr, _
     ByVal nOutBufferSize As Int32, ByRef lpBytesReturned As Int32, _
     ByVal lpOverlapped As System.Threading.NativeOverlapped) As Boolean
   End Function

User-Defined Types:

None.

Notes:

hDevice - To retrieve a handle to a volume, call CreateFile with the lpFileName parameter set to a string of the following form: \\.\DriveLetter:. DriveLetter is not case-sensitive and does not require a colon after it.

Example:

tHandle = CreateFile(@"\\.\C:", FileAccess.Read, FileShare.ReadWrite, IntPtr.Zero, FileMode.Open, 0, IntPtr.Zero)

lpOverlapped - Main use in asynchronous deviceIoControl. NativeOverlapped is the managed version of the structure and use is the same. The difference between NativeOverlapped and Overlapped is managed Struct vs managed Class respectively. NativeOverlapped was more condusive for one-way device driver communication. Convert from Overlapped to NativeOverlapped to make the call, since NativeOverlapped is explicitly defined to mimic the unmanaged Overlapped structure.

Tips & Tricks:

This is great for interacting with devices; now perhaps someone can help with the SetupDi calls to actually discover the device handles, etc...? If you are able to conquer it (I wasn't) toss me a mail at dotnet at richardgoodwin dot com

-

Sample Code:

Public ReadOnly Property CardID() As String
  Get
   Dim dwErrorCode As FarcConstants
   Dim dwBytesReceived As Int32
   Dim ip As IntPtr = Marshal.AllocHGlobal(13)
   Dim erg As String
   If DeviceIoControl(hDriver, IOCTL_FARC_GET_CARDID, Nothing, 0, ip, 13, dwBytesReceived, Nothing) Then
     erg = Marshal.PtrToStringAnsi(ip)
     Marshal.FreeHGlobal(ip)
   Else
     dwErrorCode = Marshal.GetLastWin32Error
     Marshal.FreeHGlobal(ip)
     Throw New InvalidOperationException("Get Card ID fails. Errorcode: " & _
       dwErrorCode.ToString, New System.ComponentModel.Win32Exception(dwErrorCode))
   End If
   Return erg
  End Get
End Property

Sample Code:

public bool DeviceIoControl( IntPtr hDevice, uint dwIoControlCode, ref long buffer, int bufferSize, ref NativeOverlapped pOverlapped)
{
    int NoReturn = 0;
    return DeviceIoControl( hDevice, dwIoControlCode, ref buffer, bufferSize, ref buffer, bufferSize, ref NoReturn, ref pOverlapped );
}

public bool PlxIntrAttach(IntPtr handle, PlxIntr intrType)
{
    // Call to PLX card to attach wait event to an Interrupts
    // Declare control code
    uint Control;
    DriverMsgs AttachMsg = DriverMsgs.MsgIntrAttach;
    Control = CtrCode( cFileDeviceUnknown, (int)AttachMsg, cMethodBuffered, cFileAnyAccess );
    // Set return variable up
    bool Status = false;
    // Initialize the "buffer"
    long DeviceBuffer = 0;

    // Fill the buffer with the interrupt bitflag
    DeviceBuffer = (long)intrType;
    // Call the P/Invoked function through masking method
    Status = DeviceIoControl( handle, Control, ref DeviceBuffer, 8, ref AdcOverlapData );
    // Return with Status
    return Status;
}

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