Is there a way to keep additional windows active when showing a modal window? - winforms

Question

I'm afraid the answer is probably no...but some background. To draw a custom border on a window where the sizing logic works beyond the visible border (as it does on windows 10) I added layered windows around the edges to capture the messages and then forward them to the central window. This worked great until the form was shown modaly, at which point all the edge windows were automatically disabled. Obviously this is by design...but I'm not sure if there is some way around it. I tried making the edge windows owned by the central window, but that didn't work.
Or maybe there is a better approach entirely.
Here's a sample of the issue:
public partial class Form1 : Form
{
public Form1()
{
}
protected override void OnClick(EventArgs e)
{
base.OnClick(e);
Form f2 = new Form();
f2.Text = "Non Modal";
f2.Show();
Form f3 = new Form();
f3.Text = "Modal";
f3.ShowDialog(this);
}
}

Answer 1

I think you can fake the modal window, so that it is not modal but disable the caller. I used this in a own project. I did it this way:
//Setup small Interface
public interface IDialog
{
//Our own Event which tell the caller if the Dialog is active/inactive
public event DialogChangedEventArgs DialogChanged;
}
//Setup EventArgs for our own Event
public class DialogChangedEventArgs : EventArgs
{
public bool DialogActive{get;}
public DialogChangedEventArgs(bool dialogActive)
{
DialogActive = dialogActive;
}
}
//Setup the Form which act as Dialog in any other form
public class Form2 : Form, IDialog
{
public event EventHandler<DialogChangedEventArgs> DialogChanged;
//If this Form is shown we fire the Event and tell subscriber we are active
private void Form2_Shown(object sender, EventArgs e)
{
DialogChanged?.Invoke(this, true);
}
//If the user close the Form we telling subscriber we go inactive
private void Form2_Closing(object sender, CancelEventArgs e)
{
DialogChanged?.Invoke(this, false);
}
}
public class Form1 : Form
{
//Setup our Form2 and show it (not modal here!!!)
private void Initialize()
{
Form2 newForm = new Form2();
newForm.DialogChanged += DialogChanged;
newForm.Show();
}
private void Form2_DialogChanged(object sender, DialogChangedEventArgs e)
{
//Now check if Form2 is active or inactive and enable/disable Form1
//So just Form1 will be disabled.
Enable = !e.DialogActive;
}
}
It's really simple. Just use an event to tell your first Form: Hey iam second Form and active. Then you can disable the first Form with while second is active. You have the full control which forms are active or not. Hope this helps.