Question

ok, the title is pretty long and should tell the problem i’m facing with.

Here is the code when minimizing to icon tray:

void MainFormResize(object sender, EventArgs e)
        {
            if (WindowState == FormWindowState.Minimized)
            {
                this.Hide();
                this.ShowInTaskbar = false;
            }
        }

When the program is already opened and in sys tray, and still someone wants to open another instance of it, then:

    private static void Main(string[] args)
            {
                bool createdNew = true;
                using (Mutex mutex = new Mutex(true, "IPADcommunicator", out createdNew))
                {
                    if (createdNew)
                    {
                        Application.EnableVisualStyles();
                        Application.SetCompatibleTextRenderingDefault(false);
                        Application.Run(new MainForm());
                    }
                    else
                    {
                        Process current = Process.GetCurrentProcess();
                        foreach (Process process in Process.GetProcessesByName(current.ProcessName))
                        {
                            if (process.Id != current.Id)
                            {
                                IntPtr handle = FindWindow(null,"IPADcommunicator");
                                SetForegroundWindow(handle);
                                ShowWindow(handle,5);

                                break;
                            }
                        }
...

Howeve, it is not working properly. The mainwindow is not restored.
I’ve googled a lot and haven’t found solutions for that problem.
Thanks in advance!

Answer 1

Calling SetForegroundWindow() on an invisible window isn’t going to work. There are many other possible failure mode, FindWindow() is a miserable one when you start passing null.

Don’t invent this yourself, .NET already has great built-in support for single instance apps. You can even get a notification when a 2nd copy starts and pass the command line. Which is what you want here, simply restore the window instead of hacking the API. The code you need is here.