Form.ShowDialog() Without Destroying Handle

Question

I am trying to show a form using Form.ShowDialog as shown below:

var f = new Form();
if(f.ShowDialog() == DialogResult.OK)
{
     ...
}
...
if(f.ShowDialog() == DialogResult.OK)
{
     ...
}

The issue is the OnHandleDestroyed is called once a dialog result is returned and the form is closed.

• Why do I care about OnHandleDestroyed? I have an OpenGL control on the form, and it disposes the Context when OnHandleDestroyed is called.
• Why don't I dispose of the form, and use ShowDialog on the new form? I am trying to reuse the form as loading the form is slow - but populating it with data is quick.

So the question is: Is it possible to use ShowDialog() without closing the form (and hiding it instead) OR to show a form modally using Show() and Hide()?

Answer 1

When you show a form using ShowDialog , after closing the form DestroyHandle will be called automatically.

To prevent the behavior you can override DestroyHandle method and write your own logic.

Example

public class MyForm : Form
{
    protected override void DestroyHandle()
    {
        if (!Modal || Disposing)
            base.DestroyHandle();
    }
}