Can I ensure my control catches the first event regardless of whether my form has focus?

Question

I am relatively new to C#. I have a window with buttons. If the window is out of focus and I click on a button the first time, the first click grabs focus for the window and

Answer 1

As far as I know, you've described an inherent Windows behaviour and as such it could be impossible to do.

An alternative is to harness 'Always on top' style of windows app which is explained here:

How to make a window always stay on top in .Net?

Answer 2

It sounds like you are describing how ToolStrips operate, which does not fire a click event unless the application has the focus.

A work around is to use your own ToolStrip and let the mouse activation give the control the focus, which in turn will then let the button fire it's click event:

public class ToolStripIgnoreFocus : ToolStrip {
  private const int WM_MOUSEACTIVATE = 0x21;

  protected override void WndProc(ref Message m) {
    if (m.Msg == WM_MOUSEACTIVATE && this.CanFocus && !this.Focused)
      this.Focus();

    base.WndProc(ref m);
  }
}

Rebuild your solution and you should see a ToolStripIgnoreFocus control available in your tool box. Try adding that to your form and then add your tool buttons accordingly.

Answer 3

This is normal windows behavior. Something that I don't think you can override (so that the click event fires, but doesn't bring your app to the foreground, and active state).

If you don't want to bring focus to the window, but still want to provide some 'interaction' with the window itself, try keyboard hooks or hotkey events. Examples:

• http://social.msdn.microsoft.com/Forums/en-US/Vsexpressvb/thread/2622427d-1e15-4f30-b01d-57b0ba054f5c
• Using global keyboard hook (WH_KEYBOARD_LL) in WPF / C#
• Low-level Keyhook
• http://www.pinvoke.net/default.aspx/user32/RegisterHotKey.html

Answer 4

This is how most Windows apps work - the app needs to have focus before it can receive click events.