Getting filehandle from serialport class

Question

Im using the serialPort class in visual C# do do some communication. But i also need to do some low level stuff. I assume the SerialPort class creates a filehandle like FileHandle = CreateFile(ComPort,.... Is there any way to get this handle??? I'm hoping to not have to write a complete new SerialPort class :)

Vulpes · Answer

If you look at the SerialPort class using a disassembler such as Reflector then when you call the Open() method an instance of an internal class called SerialStream is created and assigned to the SerialPort's private field internalSerialStream. The SerialStream in turn creates a file and stores a SafeFileHandle to it in its internal _handle field. The SafeFileHandle wraps the native handle (of type IntPtr) in its protected handle field. It should be possible to get at this handle using reflection. The following code compiles OK and should work though I haven't been able to test it as the laptop I'm using right now doesn't have a serial port: using System; using System.IO.Ports; using System.Reflection; using Microsoft.Win32.SafeHandles; class Program { static void Main() { SerialPort sp = new SerialPort(); // use default settings sp.Open(); Type t = typeof(SerialPort); BindingFlags bf = BindingFlags.Instance | BindingFlags.NonPublic; FieldInfo fi = t.GetField(internalSerialStream bf); object ss = fi.GetValue(sp); Type t2 = fi.FieldType; FieldInfo fi2 = t2.GetField(_handle bf); SafeFileHandle _handle = (SafeFileHandle)fi2.GetValue(ss); Type t3 = typeof(SafeFileHandle); FieldInfo fi3 = t3.GetField(handle bf); IntPtr handle = (IntPtr)fi3.GetValue(_handle); sp.Close(); Console.WriteLine(handle); Console.ReadKey(); } }

Geir Ludde · Answer

Thanks works fine :)