Using Reflection to call a function in a dll is not working

Question

Here is the code from the dll:

  public static bool SendCommand(string command)
    {

        KillTeraTerm();

        try
        {
            SerialPort portToUse = new SerialPort("COM2");

            portToUse.Open();
            portToUse.WriteLine(command);
            portToUse.Close();

            StartTeraTerm();

            return true;

        }
        catch
        {
            return false;
        }

    }

Here is the code I am using to reference the dll:

        Assembly loadedDLL = Assembly.LoadFile(@"G:\PRODUCT VALIDATION GROUP\SOFTWARE VALIDATION\Ranorex Support Files\RTSInterface.dll");
        Type rtsObj = loadedDLL.GetType("Oe.RTS.RTSInterface");
        Object obj = Activator.CreateInstance(rtsObj);

        try
        {
            rtsObj.InvokeMember("SendCommand", BindingFlags.InvokeMethod | BindingFlags.Static | BindingFlags.Public, null, obj, new object[] { "startbutton" });
        }
        catch (Exception ex)
        {
                MessageBox.Show(ex.Message);
        }

I know i am not using the return value yet... just want to know why this isnt working.

EDIT!!!!

First exception: Message = "Exception has been thrown by the target of an invocation."

Inner Exception Message = "Request failed." '

DeclaringMethod = 'rtsObj.DeclaringMethod' threw an exception of type 'System.InvalidOperationException'

Thanks for your help. First time using reflection so sorry for the choppy code.

EDIT #2!!!

Stack Trace from VS: Saftey Door Simulator.exe!Safety_Door_Simulator.Form1.btnInit_Click(object sender = {Text = "Initialize"}, System.EventArgs e = {X = 56 Y = 10 Button = Left}) Line 46 C# [External Code] Saftey Door Simulator.exe!Safety_Door_Simulator.Program.Main() Line 17 + 0x1d bytes C# [External Code]

EDIT #3

Inner stack trace:

StackTrace = " at Oe.RTS.RTSInterface.KillTeraTerm()\r\n at Oe.RTS.RTSInterface.SendCommand(String command)"

Code for KillTeraTerm:

   public static void KillTeraTerm()
    {
        if (Process.GetProcessesByName("ttermpro").Length != 0)
        {
            Process[] teraTermProcess = Process.GetProcessesByName("ttermpro");

            foreach (Process p in teraTermProcess)
            {
                p.Kill();
                Thread.Sleep(1000);
            }

        }
    }

Answer 1

Do not use Assembly.LoadFile(), it loads assemblies without a loading context. Use LoadFrom() instead.

The exception message is pretty meaningless, not the kind you'd get out the .NET framework code. You need to look at the stack trace of the InnerException to know where it got raised.