Question

Rep steps:

1. create example .NET form application
2. put a TextBox on the form
3. wire a function up to the TextBox’s Enter event

When you run this application, the Control.Enter event fires when focus first goes to the TextBox. However, if you click away into another application and then click back into the test application, the event will not fire again.

So moving between applications does not trigger Enter/Leave.

Is there another alternative Control-level event that I can use, which will fire in this scenario?

Ordinarily, I would use Form.Activated. Unfortunately, that is troublesome here because my component is hosted by a docking system that can undock my component into a new Form without notifying me.

Answer 1

If I try your example and click outside the control on another window, desktop, etc, I can get the Got and Lost Focus events to fire, but if you’re only trying to click within a form or a control with only 1 control, these event will never be fired because it is the only thing to focus on. Neither will Entered or left, unless you change the dynamics or overload the controls, you cannot get this to happen