How to create a form on its own thread and keep it open throughout application lifetime

Question

I am creating a little testing component and am running into a problem

Basically the component is a decorator on a class that controls all access to the database, it creates a form with a two buttons on it: "Simulate Lost Connection" and "Reconnect". Press the button, and instead of letting function calls pass through the wrapper starts throwing NoConnectionException()s nice and simple, and real helpful for testing.

The problem is that this particular application when it detects a lost connection raises a modal dialog box "connection lost!" that sits there until the connection is regained. Because it is modal I cannot press my nifty button to simulate regained connectivity.

What I need to do therefore is to run my little testing form in a different thread. I'm not absolutely sure how to do that. I tried

new Thread(
  new ThreadStart(
    (Action)delegate {_form.Start();}
  )
).Start();

But the thread closes as soon as the method returns so the form never shows up except for an instant.

Any idea how I go about achieving what I want?

Answer 1

It sounds like you aren't holding on to your thread. It's an object, like everything else, so if it is scoped to your method, it will fall out of scope once your method exits. Try making it an instance variable.

Answer 2

You will need to start a message loop on the newly created thread. You can do that by calling Application.Run(form).

Answer 3

Try

new Thread(
  new ThreadStart((Action)delegate {
        _form.Start();
        System.Windows.Forms.Application.Run();
    }
  )
).Start();

Answer 4

in fact there is the solution : use showdialog : System.Threading.Thread t = new System.Threading.Thread(new form1().ShowDialog()); t.Start();