Hi,
I am a newbie to C# and Im trying to redirect standard input and output of a console program written in C (MS VC 6.0) to a textbox on a form. The code for the redirecting looks like this:

private System.IO.StreamWriter c_StreamInput = null;
private System.IO.StreamReader c_StreamOutput = null;
private Thread c_ThreadRead = null;
private Process c_Process = null;

private void ReadStdOutputThreadProc()
{
while(!c_Process.HasExited)
{
try
{
string str = c_StreamOutput.ReadLine();
while (str != null)
{
c_StreamOutput.BaseStream.Flush();
txtboxCNF.AppendText(str + "\r\n");
Thread.Sleep(100);
str = c_StreamOutput.ReadLine();
}
}
catch (Exception) { }
}
}

private void btnCNF_Click(object sender, System.EventArgs e)
{
if(c_Process == null)
{
c_Process = new Process();
ProcessStartInfo psi = new ProcessStartInfo("console.exe");
psi.UseShellExecute = false;
psi.RedirectStandardOutput = true;
psi.RedirectStandardInput = true;
psi.CreateNoWindow = true;
c_Process.StartInfo = psi;
c_Process.Start();

c_StreamInput = c_Process.StandardInput;
c_StreamOutput = c_Process.StandardOutput;

c_StreamInput.AutoFlush = true;

c_ThreadRead = new Thread(new ThreadStart(ReadStdOutputThreadProc));
c_ThreadRead.IsBackground = true;
c_ThreadRead.Start();
}
}

private void Form1_Closing(object sender, System.ComponentModel.CancelEventArgs e)
{
if (c_ThreadRead != null)
{
c_ThreadRead.Abort();
c_ThreadRead.Join();
}
if(c_Process != null && !c_Process.HasExited)
c_Process.Kill();
}

private void txtboxCNF_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e)
{
if(e.KeyValue == 13)
{
c_StreamInput.WriteLine((char)e.KeyValue+"\0\n");
}
}

The console application that I am trying to run (console.exe) is a simple C program that prints a line text and then calls the gets() function. The code is basically this:

#include "stdafx.h"
#include <conio.h>
#include <string.h>

void create_it();

int main(int argc, char* argv[])
{
create_it();

return 1;
}

void create_it()
{
char str_nodes[256], str_filename[256], str_username[256], str_serial[256];

printf("Welcome to the console program\n");

/* Display maximum number of nodes */
printf ("Max Nodes : ");
gets( str_nodes);

/* get file name */
printf ("Enter user configuration file name : ");
gets (str_filename);

/* get user name */
printf ("User Name : ");
gets (str_username);

/* get serial number */
printf ("Serial Id : ");
gets (str_serial);
}

The problem is that I am not able to use the console app interactively using the text box on the form. Is there any way I can get it to work so that what I type into the textbox goes into the console app as its standard input?

Thanks in advance for your help.

Hi!

I don't know if that's the problem, but your txtboxCNF_KeyDown method seems rather strange. You check for the character code 13, and then write the same code plus some bogus 0 character to the stream.

c_StreamInput.WriteLine((char)e.KeyValue+"\0\n");

This would essential write "\n\0\n" to the stream everytime someone presses the enter key. I think you should have here something like:

c_StreamInput.WriteLine ( textboxCNF.Text );

So you write whatever is in your textbox at that moment, and not the current key pressed(which would be enter). You do not need to include the line feed for WriteLine method. You also might want to clear the textbox after writing its contents to the stream, so a new line of input can be added.

Another problem might come from the fact that you modify the contents of controls from another thread. It is not always a good idea to directly access the controls that were created on the UI thread from the working thread. Consider using the Invoke method that is available for your Form (actually inherited from Control).

Hope this helps!

Lenard

I have tried your suggestion, but it doesn't seem to help. My code now looks like this (if that helps):

private void ReadStdOutputThreadProc()

{

while(!c_Process.HasExited)

try

string str = c_StreamOutput.ReadLine();

while (str != null)

txtboxCNF.AppendText(str + "\r\n");

Thread.Sleep(100);

catch (Exception) { }

private void CNFOutputHandler(object sendingProcess, DataReceivedEventArgs outLine)

// Collect the sort command output.

if (!String.IsNullOrEmpty(outLine.Data))

txtboxCNF.AppendText(outLine.Data + "\r\n");

private void btnCNF_Click(object sender, System.EventArgs e)

if(c_Process == null)

c_Process = new Process();

ProcessStartInfo psi = new ProcessStartInfo("C:\\XPDistribution\\console.exe");

psi.UseShellExecute = false;

psi.RedirectStandardOutput = true;

//c_Process.OutputDataReceived += new DataReceivedEventHandler(CNFOutputHandler);

psi.RedirectStandardInput = true;

psi.CreateNoWindow = true;

c_StreamInput.AutoFlush = true;

c_ThreadRead = new Thread(new ThreadStart(ReadStdOutputThreadProc));

c_ThreadRead.IsBackground = true;

//c_Process.BeginOutputReadLine();

private void Form1_Closing(object sender, System.ComponentModel.CancelEventArgs e)

if (c_ThreadRead != null)

if(c_Process != null && !c_Process.HasExited)

private void txtboxCNF_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e)

if (e.KeyValue == 13)

_inputBuffer.Append('\0');

_inputBuffer.Append('\n');

String input = _inputBuffer.ToString();

else