WinForms: How to Handle Mouse Click Events on Overlay Controls Without Interference?
I tried several approaches but none seem to work. I'm currently developing a WinForms application where I have a main form with a transparent overlay that displays progress during long-running tasks. The overlay is a Panel control that covers the entire form but is supposed to be transparent to mouse clicks so that the user can still interact with the controls behind it. However, I'm experiencing issues: clicks on the overlay are being captured by the overlay itself instead of passing through to the underlying controls. I've tried setting the `Enabled` property of the overlay to `false`, but doing so makes it non-interactable and doesn't display the progress correctly. I've also attempted to subclass the Panel and override the `WndProc` method to ignore mouse clicks, but that leads to unexpected behaviors like flickering when the overlay is shown or hidden. Here's the code snippet I used: ```csharp public class TransparentPanel : Panel { protected override void WndProc(ref Message m) { const int WM_MOUSEACTIVATE = 0x0021; if (m.Msg == WM_MOUSEACTIVATE) return; base.WndProc(ref m); } } ``` I create the overlay like this: ```csharp TransparentPanel overlay = new TransparentPanel(); overlay.BackColor = Color.FromArgb(128, Color.Black); overlay.Dock = DockStyle.Fill; this.Controls.Add(overlay); ``` The flickering issue occurs because the overlay is being shown and hidden frequently based on task completion. Another approach I considered was to use `Control.SetStyle()` to add `ControlStyles.SupportsTransparentBackColor`, but that didn't yield the desired results either. Is there a recommended way to handle mouse clicks on a transparent overlay in WinForms so that they don't interfere with the controls behind it while still ensuring a smooth user experience? Any advice or best practices would be greatly appreciated! My development environment is Windows.