Question

I’d like to show an input modal in my WinForm application. I have looked around the web, but haven’t found a good pattern for doing this. I understand I’d have to create another Form, and use the ShowDialog method.

Answer 1

You are correct.

Note that modal dialogs are not automatically disposed when closed (unlike non-modal dialogs), so you want a pattern like:

using (FrmModal myForm = new FrmModal())
{
    DialogResult dr = myForm.ShowDialog();
    if (dr == DialogResult.OK)
    {
        // ...
    }
    else
    {
        // ...
    }
}

In the new form itself (which I have called FrmModal), set the DialogResult property in your button event handlers appropriately, e.g. if you have an OK button you would want to set DialogResult = DialogResult.OK in the event handler for that button and then call Close() to close the form.