Redirecting cmd Output to textBox

Question

I'm Re-Creating the "command prompt" into a Windows Form. The application is not working properly; and i can't figure exactly why.

When the form Loads it is suposed to run the cmd.exe (Load the cmd info into "TextBox_Receive"), but it doesnt; and also after writing any command in the "textBox_send" (that sends input); it will only show input after pressing "Enter" key 2 or 3 times.

Any idea what i am missing here?

public partial class Form1 : Form
{
    // Global Variables:
    private static StringBuilder cmdOutput = null;
    Process p;
    StreamWriter SW;

    public Form1()
    {
        InitializeComponent();
        textBox1.Text = Directory.GetCurrentDirectory();
        // TextBox1 Gets the Current Directory
    }

    private void Form1_Load(object sender, EventArgs e)
    {
        checkBox1.Checked = true;
        // This checkBox activates / deactivates writing commands into the "textBox_Send"

        cmdOutput = new StringBuilder("");
        p = new Process();

        p.StartInfo.FileName = "cmd.exe";
        p.StartInfo.UseShellExecute = false;
        p.StartInfo.CreateNoWindow = true;
        p.StartInfo.RedirectStandardInput = true;
        p.StartInfo.RedirectStandardOutput = true;
        p.StartInfo.RedirectStandardError = true;
        p.EnableRaisingEvents = true;

        p.OutputDataReceived += new DataReceivedEventHandler(SortOutputHandler);

        p.Start();

        SW = p.StandardInput;

        p.BeginOutputReadLine();
        p.BeginErrorReadLine();            
    }

    private static void SortOutputHandler(object sendingProcess, DataReceivedEventArgs outLine)
// I dont actually understand this part of the code; as this is a "copy" of a snippet i found somewhere. Although it fixed one of my issues to redirect.
    {
        if (!String.IsNullOrEmpty(outLine.Data))
        {
            cmdOutput.Append(Environment.NewLine + outLine.Data);
        }
    }

    private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
    {
        // Send "Enter Key" - Send Command
        if (e.KeyChar == 13)
        {
            SW.WriteLine(txtbox_send.Text);
            txtbox_receive.Text = cmdOutput.ToString();
            txtbox_send.Clear();
        }
    }

    private void checkBox1_CheckedChanged(object sender, EventArgs e)
    {
        // Enable / Disable Sending Commands
        if (checkBox1.Checked)
            txtbox_send.Enabled = true;
        else
            txtbox_send.Enabled = false;
    }
}

}

score 1 · Answer 1 · answered May 11 '13 at 01:43

1

You might also try capturing the error data.

To do this:

after your line

p.OutputDataReceived += new DataReceivedEventHandler(SortOutputHandler);

enter this line

p.ErrorDataReceived += new DataReceivedEventHandler(SortOutputHandler);

It might also be a problem with cmd.exe.

answered May 11 '13 at 01:43

jamesthollowell

1,550
15
21

Thanks! I forgot about that. – May 11 '13 at 16:52

score 0 · Accepted Answer · answered May 10 '13 at 23:42

I think your issue is the use of OutputDataReceived. In the documentation:

The event is enabled during asynchronous read operations on StandardOutput. To start asynchronous read operations, you must redirect the StandardOutput stream of a Process, add your event handler to the OutputDataReceived event, and call BeginOutputReadLine. Thereafter, the OutputDataReceived event signals each time the process writes a line to the redirected StandardOutput stream, until the process exits or calls CancelOutputRead.

See the example code on that page for more details.

However - I'm not sure you need to go that route. Have you tried just reading directly from the StandardOutput stream?

Thanks! =) I've Re-made the Code and redirects perfectly! – May 11 '13 at 16:52 — , May 11 '13 at 16:52

Redirecting cmd Output to textBox

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