Question

Using the ultra-simple code below, as soon as I press a key on my keyboard while the form is in focus, the form completely locks up. I’m running this inside of F# interactive. The only way to close the form is by clicking “Reset Session” in F# interactive. I’ve tried adding event handlers to KeyPress, with the same results. I’ve had no problem adding mouse event handlers, menus, combo boxes etc.

I must be doing something wrong, as something as obvious as pressing a key on a keyboard probably shouldn’t be a bug at this point for F#. Any ideas?

// Add reference to System.Windows.Forms to project
open System.Windows.Forms

let a = new Form()
a.Visible <- true

I’m using F# 2.0 for Windows + Visual Studio 2008 (April 2010 release) on Windows XP.

Thanks!

Answer 1

I think you need a call to

Application.Run(a)

but I don’t have time to try and verify right now.

EDIT:

A useful thing to do is: create a C# Windows Form project, and see what code it starts you off with. It gives you this:

    [STAThread]
    static void Main()
    {
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        Application.Run(new Form1());
    }

so of course you can do the same in F#:

open System.Windows.Forms 

let Main() =
    Application.EnableVisualStyles()
    Application.SetCompatibleTextRenderingDefault(false)
    Application.Run(new Form())

[<System.STAThread>]
do
    Main()