How to be OnTop but not OnTop of a full screen application

Question

So I have tried searching for the better part of a day for the answer to a simple question. I want my C# application to popup another winform on a timer and then close it after a delay. Simple enough, done and done. Now my issue is that I want it to actually be on top of other applications UNLESS they are full screen. By that I mean a true full screen application such as a game. I do not want to interfere with such an application since it should take priority over my application.

The issue is that I am using the 'OnTop' property on the popup form and, while it works perfectly for any other applications I have been testing it while playing a full screen game and the form, when it "Show()"s, takes the full screen application and drops it into windowed mode.

Is this the intended effect of the 'OnTop' property with full screen applications? If so is there a way that I can have my form popup on top of normal windowed windows and not interfere with full screen applications?

Any links, example, a kick in the general direction is great. The only hits that I come up with when searching for winforms involving full screen is people trying to get their application into full screen or having their application take focus away from another application.

Thanks on advance.

(I didn't post any code due to it just being a simple winform that is "formX:Show()" on a timer with the "onTop" property set)

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(EDIT) So thanks to awilson53 for putting me on the right track I was able to find a method (albeit somewhat picky) to determine if an application is full screen. Seems kinda simple, and an "well duh", answer after all is said and done.

95% of the credit goes to the author of the article: http://www.richard-banks.org/2007/09/how-to-detect-if-another-application-is.html

~5% goes to awilson53 for getting me on the right track. :)

Answer 1

Check out this wrapper for the EnumWindows function. This will allow you to enumerate all open windows and determine their window state. You will want to check the EnumWindowItem.Maximized property, and if it is true set your OnTop property to false. If none of the EnumWindowItem's return Maximised you can set OnTop to true.