wait for process within process

Question

Im trying to build a cmd.exe wrapper but i cant figure out how to wait for a process inside the cmd process to finish.

When im run ping.exe in my program, my "inputline" (the path) will output to the console before the ping-command is finished.

I cant use: .WaitForInputIdle(); because I don't have a GUI. "This could be because the process does not have a graphical interface."

Is it even possible to solve or is there any better way to do it?

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

namespace ObjectTest
{
    class cmd
    {
        Process cmdProcess;
        StreamWriter cmdStreamWriter;

        public cmd()
        {
            //WinAPI.ShowConsoleWindow();
            Process();
            //WinAPI.HideConsoleWindow();
        }

        private void Process()
        {
            StartCmd();
            string command = "";
            while (command != "exit")
            {

                Thread.Sleep(100);
                cmdProcess.WaitForInputIdle();
                Console.Write(Environment.NewLine + Directory.GetCurrentDirectory() + "> ");
                command = Console.ReadLine();
                SendCommand(command);
            }
        }


        private void StartCmd()
        {
            cmdProcess = new Process();

            cmdProcess.StartInfo.FileName = "cmd.exe";
            cmdProcess.StartInfo.UseShellExecute = false;
            cmdProcess.StartInfo.CreateNoWindow = true;
            cmdProcess.StartInfo.RedirectStandardOutput = true;
            cmdProcess.OutputDataReceived += new DataReceivedEventHandler(SortOutputHandler);
            cmdProcess.ErrorDataReceived += new DataReceivedEventHandler(SortOutputHandler);
            cmdProcess.StartInfo.RedirectStandardInput = true;
            cmdProcess.Start();

            cmdStreamWriter = cmdProcess.StandardInput;
            cmdProcess.BeginOutputReadLine();
        }

        private void SendCommand(string command)
        {
            cmdStreamWriter.WriteLine(command);
        }

        private void btnQuit_Click(object sender, EventArgs e)
        {
            cmdStreamWriter.Close();
            cmdProcess.WaitForExit();
            cmdProcess.Close();
        }

        private static void SortOutputHandler(object sendingProcess, DataReceivedEventArgs outLine)
        {
            if (!string.IsNullOrEmpty(outLine.Data))
            {
                Console.WriteLine(outLine.Data);
            }
        }


    }
}

Answer 1

If it's only actual processes you want to catch you can use polling methods as such:

1. Before running the command, collect all existing processes of, for example, ping (.exe), using Process.GetProcessesByName, and store their PIDs.

2. Run the command

3. In order to wait for exit, Again scan for all ping processes, and wait on all processes that did not previously exist.

Note that this will fail, or at least not be accurate, if another process will launch another ping between steps 1 and 3.

You should also keep in mind that CMD does not wait on all type of processes, only those which are defined as console applications (see this question).

Answer 2

When starting a process, you can specify that you want to wait:

var process = Process.Start(...);
process.WaitForExit();

Here's a link to MSDN explaining it: http://msdn.microsoft.com/en-us/library/fb4aw7b8(v=vs.110).aspx

I think this is wat you need.