Yes, by using PInvoke.

There is nothing to link or include, you need to declare the function in C#,
the runtime will dynamically load and call the function from the DLL.
As an example, following are the PInvoke declarations (C#) for the
kernel32.dll API's CreateFile, DeviceIoControl and CloseHandle.

       [DllImport("kernel32.dll", CharSet = CharSet.Auto,
SetLastError=true)]
       static extern SafeFileHandle CreateFile(string lpFileName, int
dwDesiredAccess, int dwShareMode,
         IntPtr lpSecurityAttributes, uint dwCreationDisposition, uint
dwFlagsAndAttributes,
         SafeFileHandle hTemplateFile);

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

        [DllImport("kernel32.dll")]
        static extern bool CloseHandle(IntPtr hObject);

note that you also need to declare all of the constants used as argument in
an API call, for instance:

       const int GENERIC_READ = unchecked((int)0x80000000);
       const int GENERIC_WRITE = unchecked((int)0x40000000);
       ..
       const int OPEN_EXISTING = 3;

In short you need to convert the header file contents related to the API you
want to use into C# style declarations.

When you are done with all this, you can call these from C# just like this:

SafeFileHandle h = CreateFile("\\\\.\\PhysicalDrive1",  GENERIC_READ, ...);

You may want to consult the PInvoke site here <http://www.pinvoke.net/>
before you start to declare some API's yourself, but watch out, some API's
are declared incorrectly, some are missing the structs constant or enum
declarations, and a large deal is simply covered by managed API's.

Willy.