How can you prevent an individual window being captured by Print-Screen?

I noticed a few times than when I print-screen while Media Player is running, the content is replaced with a grey rectangle. I've no idea if it's deliberate due to DRM, or some technical issue, but it struck me that being able to deliberately block screen-capture might be a useful feature in some scenarios. I am not looking to fix the 开发者_如何学运维problem, but replicate it!

Is there some specific message each HWND gets for print-screen - does Windows do a special repaint or simply dump buffers to the clipboard?

I guess I'd prefer to focus this on Win32 specifically, but as long as it's Windows-related then fine.

You can register a hotkey, using this method. Register the PrtScr key and your application will receive a message in your WndProc, WM_HOTKEY. Once you recieve that, you can do something to your form to blank out the display, or something else.

That hotkey method should work even if your form is minimised.

You have to turn off 'Use overlays' to be able to take a screenshot.

Open Windows Media player. Select "Tools" -> "Options..." from the menu. Click on "Performance" tab. Click on "Advanced..." button. Uncheck "Use overlays" checkbox in the "Video Acceleration" group. Click on "OK" button. Click on "OK" button