How to set/change/remove focus style on a Button in C#?

Question

I have a couple of buttons of which I modified how they look. I have set them as flat buttons with a background and a custom border so they look all pretty and nothing like

Answer 1

The second border which gets added is the Windows standard "default button" border. You may have noticed that if you tab through most dialog boxes with multiple buttons (such as any Control Panel properties window), the original "double-bordered" button becomes "normal," and the in-focus button becomes "double-bordered."

This isn't necessarily focus at work, but rather a visual indication of the action undertaken by hitting the Enter key.

It sounds, to me, like you don't really care about that internal working. You want the display to not have two borders -- totally understandable. The internal working is to explain why you're seeing this behavior. Now ... To try and fix it.

The first thing I'd try -- and bear in mind, I haven't validated this -- is a hack. When a button receives focus (thereby getting the double-border), turn off your single border. You might get the effect you want, and it's pretty simple. (Hook into the Focus event. Even better, subclass Button and override OnFocus, then use that subclass for your future buttons.)

However, that might introduce new, awkward visual side effects. In that vein -- and because hacks are rarely the best answer -- I have to "officially" recommend what others have said: Custom paint the button. Although the code here may be overkill, this link at CodeProject discusses how to do that (VB link; you'll need translate). You should, in a full-on custom mode, be able to get rid of that second border completely.