Using bash(cygwin) inside C# program

i need to use bash shell "inside" C# program. I want to mimic user typing in interactive mode and running cygwin commands.

i created a process that runs bash and redirect stdin,stout and std error but i can;t get tty to work attached is a sample code that starts bash process and redirect the input/output.

the problem is that i don't have tty device. if i try to run tty command or stty command i receive error response

tty - not a tty 
stty - Inappropriate ioctl for device

i think the this is caused from psi.UseShellExecute = false;

i need to run cygwin and disable echo with stty -echo but to do this i need a tty device. how ca i create a cygwin bash shell with tty device and redirect the stdin, out and error ?

1) what am missing ?

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading;

namespace shartCygwin
{
    class Program
    {
        private static Queue<string> ResponseQueue = null;
        private static ManualResetEvent ResponseEvent = null;

        static void Main(string[] args)
        {
            ResponseQueue = new Queue<string>();
            ResponseEvent = new ManualResetEvent(false);

            Process bashProcess = new Process();

            bashProcess.StartInfo.FileName = "C:\\cygwin\\bin\\bash.exe"; 
            bashProcess.StartInfo.Arguments = "--login -i ";  
            bashProcess.StartInfo.WorkingDirectory = "C:\\cygwin\\bin";

            bashProcess.StartInfo.EnvironmentVariables["CYGWIN"] = "tty";

            bashProcess.StartInfo.RedirectStandardError = true;
            bashProcess.StartInfo.RedirectStandardInput = true;
            bashProcess.StartInfo.RedirectStandardOutput = true;
            bashProcess.StartInfo.CreateNoWindow = true;
            bashProcess.StartInfo.UseShellExecute = false;
            bashProcess.StartInfo.ErrorDialog = false;

            bashProcess.Start();

            DataReceivedEventHandler errorEventHandler = new DataReceivedEventHandler(ErrorDataReceived);
            DataReceivedEventHandler outEventHandler = new DataReceivedEventHandler(OutDataReceived);
            bashProcess.OutputDataReceived += outEventHandler;
            bashProcess.ErrorDataReceived += errorEventHandler;
            bashProcess.BeginErrorReadLine();
            bashProcess.BeginOutputReadLine();

            while(true)
            {
                Thread.Sleep(1000);
            }
        }

        static void ErrorDataReceived(object sender, DataReceivedEventArgs dataReceivedEventArgs)
        {
            try
            {
                lock (ResponseQueue)
                {
                    Console.WriteLine(dataReceivedEventArgs.Data);
                    ResponseQueue.Enqueue(dataReceivedEventArgs.Data);
                    ResponseEvent.Set();
                }
            }
            catch (Exception e)
            {
                Console.WriteLine(e.Data);
            }
        }

        static void OutDataReceived(object sender, DataReceivedEventArgs dataReceivedEventArgs)
        {
            try
            {
                lock (ResponseQueue)
                {
                    Console.WriteLine(dataReceivedEventArgs.Data);
                    ResponseQueue.Enqueue(dataReceivedEventArgs.Data);
                    ResponseEvent.Set();
                }
            }
            catch (Exception e)
            {
                Console.WriteLine(e.Data);
            }
        }
    }
}