Process ID of process Started by Process Start

Question

I am trying to kill the process by process ID which I am saving when the process start. But the process ID which I am capturing doesn't exists when I try to kill the process from code behind.

This is the code below to start the process and capture the process ID.

private List<int> pids = new List<int>();
public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            pids.Clear();
            Process myprocess= new Process();

            myprocess.StartInfo.FileName = Environment.ExpandEnvironmentVariables(@"%SystemRoot%\system32\cmdkey.exe");
            myprocess.StartInfo.Arguments = "C:\\rdp\\RemoteIn.rdp";
            myprocess.Start();
            pids.Add(myprocess.Id);          
        }

        private void terminateAll()
        {
            //foreach (var p in pids) p.Kill();

            foreach (var i in pids)
            {
                Process p = Process.GetProcessById(i);
                p.Kill();

            }
        }

        private void button2_Click(object sender, EventArgs e)
        {
            terminateAll();
        }

When I click button to terminate the process it shows following error.

Is there any way to fix this.

After using Palani Kumar code, I am getting below exception.

Form Looks like this

Answer 1

I don't know why you are declared pids as List<int> and cleared the list (pids.Clear();) on button click event. Anyway the below will work for creating multiple processes also.

EDIT: As so far discussed with Amrit. The Windows 8 creating sub processes for mstsc with connecting same domain. So I slightly modified my code.

    private void button1_Click(object sender, EventArgs e)
    {
        //pids.Clear();
        Process myprocess = new Process();

        myprocess.StartInfo.FileName = Environment.ExpandEnvironmentVariables(@"%SystemRoot%\syswow64\mstsc.exe");
        myprocess.StartInfo.Arguments = "C:\\rdp\\RemoteIn.rdp";
        myprocess.Start();
        Thread.Sleep(100);
        /* Edit */
        Process proc = Process.GetProcessesByName("mstsc").FirstOrDefault(x => !pids.Any(y => y == x.Id));
        if(proc != null)
        {
           pids.Add(proc.Id);
        }
    }

And

    private void terminateAll()
    {
        foreach (var i in pids)
        {
            try
            {
                Process p = Process.GetProcessById(i);
                p.Kill();
            }
            catch (Exception ex)
            {
                //throw exception if we close the mstsc manually
            }
        }
    }