I have a form with 3 controls:
What I want is for the user to enter commands in the first textbox, press the button to enter and receive feedback via the second textbox.
I know how to use ProcessStartInfo.RedirectStandardOutput
but, however, the app hangs when I use StandardOutput.ReadToEnd()
.
I had a look at the asynchronous Process.BeginOutputReadLine()
but, even though my app does not hang, somehow I get no response in the textbox, it does absolutely nothing.
Here's my code:
public partial class MainForm : Form
{
private void MainForm_Load(object sender, EventArgs e)
{
InitializeInterpreter();
}
private void InitializeInterpreter()
{
InterProc.StartInfo.UseShellExecute = false;
InterProc.StartInfo.FileName = "app.exe";
InterProc.StartInfo.RedirectStandardInput = true;
InterProc.StartInfo.RedirectStandardOutput = true;
InterProc.StartInfo.RedirectStandardError = true;
InterProc.StartInfo.CreateNoWindow = true;
InterProc.OutputDataReceived += new DataReceivedEventHandler(InterProcOutputHandler);
InterProc.Start();
}
private static void InterProcOutputHandler(object sendingProcess, DataReceivedEventArgs outLine)
{
if (!String.IsNullOrEmpty(outLine.Data))
{
OutputTextBox.Append(Environment.NewLine + outLine.Data);
}
}
private void Enterbutton_Click(object sender, EventArgs e)
{
InterProc.StandardInput.Write(CommandtextBox.Text);
InterProc.BeginOutputReadLine();
}
}
Is there any way I can have this run smoothly? Thanks.
If you want something interactive, I got this code to work (yours modified, details on modifications below)
private void InitializeInterpreter()
{
InterProc.StartInfo.UseShellExecute = false;
InterProc.StartInfo.FileName = "Echoer.exe";
InterProc.StartInfo.RedirectStandardInput = true;
InterProc.StartInfo.RedirectStandardOutput = true;
InterProc.StartInfo.RedirectStandardError = true;
InterProc.StartInfo.CreateNoWindow = true;
InterProc.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
InterProc.OutputDataReceived += new DataReceivedEventHandler(InterProcOutputHandler);
bool started = InterProc.Start();
InterProc.BeginOutputReadLine();
}
private void AppendTextInBox(TextBox box, string text)
{
if (this.InvokeRequired)
{
this.Invoke((Action<TextBox, string>)AppendTextInBox, OutputTextBox, text);
}
else
{
box.Text += text;
}
}
private void InterProcOutputHandler(object sendingProcess, DataReceivedEventArgs outLine)
{
AppendTextInBox(OutputTextBox, outLine.Data + Environment.NewLine);
}
private void Enterbutton_Click(object sender, EventArgs e)
{
InterProc.StandardInput.WriteLine(CommandTextBox.Text);
}
So, I moved the BeginOutputReadLine to just after the process is started. That ensures it's really only called once. I also did an invoke required to clean up thread calls. Hopefully this should work for you.