The base implementation of a dialog that registers and unregisters itself against the WindowHandler

BaseDialog.cs

public class BaseDialog : Form
{
    protected override void OnShown(EventArgs e)
    {
        WindowHandler.AddDialogForTesting(this);
        base.OnShown(e);
    }

    protected override void OnClosed(EventArgs e)
    {
        WindowHandler.RemoveDialogFromTesting(this);
        base.OnClosed(e);
    }
}