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Toggle Process.StartInfo.WindowStyle = ProcessWindowStyle.Hidden at runtime

I want to toggle a process's visibility at runtime, I have a Windows Form app that starts via a process another console app hidden by default but I'd like to allow the admin user to toggle this state via a checkbox and show the console app if they choose.

I have this but it's not working:

private void checkBox1_CheckedChanged(object sender, EventArgs e)
    {
        ProcessWindowStyle state = cvarDataServiceProcess.StartInfo.WindowStyle;
        if (state == ProcessWindowStyle.Hidden)
            cvarDataServiceProcess.StartInfo.WindowStyle = ProcessWindowStyle.Normal;
        else if (state == ProcessWindowStyle.Normal)
            cvarDataServiceProcess.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;            
    }
like image 314
m3ntat Avatar asked Sep 02 '25 17:09

m3ntat


2 Answers

You have to use Win32 API for this.

    [DllImport("user32.dll")]
    static extern bool ShowWindow(IntPtr hWnd, int nCmdShow);

    ProcessWindowStyle state = ProcessWindowStyle.Normal;

    void toggle()
    {
        if (cvarDataServiceProcess.HasExited)
        {
            MessageBox.Show("terminated");
        }
        else
        {
            if (cvarDataServiceProcess.MainWindowHandle != IntPtr.Zero)
            {
                if (state == ProcessWindowStyle.Hidden)
                {
                    //normal
                    state = ProcessWindowStyle.Normal;
                    ShowWindow(cvarDataServiceProcess.MainWindowHandle, 1);
                }
                else if (state == ProcessWindowStyle.Normal)
                {
                    //hidden
                    state = ProcessWindowStyle.Hidden;
                    ShowWindow(cvarDataServiceProcess.MainWindowHandle, 0);
                }
            }
        }
    }

This, however, will not work when the process is started hidden, because the window will not be created and the handle to main window will be zero (invalid).
So, maybe you can start the process normally and then hide it after that. :)

like image 60
Nayan Avatar answered Sep 05 '25 16:09

Nayan


Instead of using Process.StartInfo.WindowStyle after the process is started, you use Process.ShowWindow() to change the window style. However, as stated above, if you start the process hidden, you can never show the process window. IMHO, this is a very annoying bug that Microsoft should fix, but alas, I just work around it by showing the window then hiding it. Not as clean, and leaves a little user interface (or task bar) flashes, but at least it works.

like image 29
Queue Avatar answered Sep 05 '25 15:09

Queue