I have a problem, a bit related to: C# Winforms Transparent Control allowing Clickthrough
Contrary to him I would like to capture mouse events on my program, while still retaining a "window" to whats behind my program. color.transparent doesn't work, and transparency key just delivers mouse events to whatever is underneath. Using a panel with transparent BackColor or with a BackColor equal to transparency key does not give the desired effect.
If you need to capture the mouse events, and that's include the MouseClick, then simply use transparency, but don't set it to 0 set it to 1.
It will be transparent enough to see through, but because it's non-zero the mouse events will be processed the the front-most window.
来源：https://stackoverflow.com/questions/2547425/c-sharp-winforms-transparent-control-allowing-clickthrough