Closing a form from the Load handler

The best way to do so :

 this.BeginInvoke(new MethodInvoker(this.Close));

this is the most simple way you wont get ObjectDisposedException

I know this is an old issue but no one seemed to have posted the obvoius answer.

You say you call Control.Show() and then Form.Close() and then the form is Disposed of. Well, unless you use MDI or use ShowDialog that's just as documented. Though, the short version of the Close() documentation is "Closes the form", it actually also disposes it implicitly under certain conditions.

See the remarks section: http://msdn.microsoft.com/en-us/library/system.windows.forms.form.close.aspx

If you want to show a form again. Use the Hide() method instead of Close().

Hope that helps other searching souls.

And guys, don't stop searching at "I don't know why it works sometimes". That becomes buggy software with lots of defensive "I'll call this method again just in case" stuff. Not good.

If you want to close a form as if the user pressed the cross in the upper right corner (usually means cancel), just add the following code.

this.DialogResult = System.Windows.Forms.DialogResult.Cancel;
this.Close();

This also works in the form load function:

private void MyForm_Load (object sender, EventArgs e)
{
    // do some initializations

    if (!ContinueLoadingForm())
    {
         this.DialogResult = System.Windows.Forms.DialogResult.Cancel;
         this.Close();
         return;
    }
    // continue loading the form
}

If you don't want the form to be visible for a short while, set the Visible property false (for example in the designer or constructor), and set it back to true when you are certain the program can continue loading.

Ok, hate to answer my own question, but this was driving me nuts, and it was one of the hardest bugs to reproduce I've ever seen.

On my form I'm overriding the OnFormLoad and OnFormClose methods, where I save/restore the form's Size, Location, and WindowState to/from the registry. I took this code out and it fixed the problem. The weird thing is, I put it back and the problem didn't come back.

I finally reproduced the problem: you have to let the form open fully, maximize it, and then close it so that the Maximized state is saved to the registry. Then when you open it again, it will set it to Maximized, and if it closes in the Load handler, it tries to access the Size/Location as it's closing. Apparently accessing these values in the OnFormClosing method causes the form to try to focus IF AND ONLY IF the form is maximized, which is illegal, since the form has been disposed.

So basically, you can't access Form display properties in the OnFormClosing method of a form, if that form is going to call Close from it's Load event.(Unless you check the Disposed prop first)

pretty specific piece of Winforms wisdom I know, but I'm writing it down anyway.