A program in C# to tell whether opened applications are in maximized mode or not

Question

I would like to know whether any libraries are available in Windows OS which allows us to capture other applications window states

Answer 1

Use PInvoke to call GetWindowPlacement.

See here for details:

http://www.pinvoke.net/default.aspx/user32/getwindowplacement.html

You can use FindWindowEx to find the handle to the window.

Answer 2

Process Hacker as a large set of libraries that can be linked against in .NET.

It should have everything you need to do what you want - and a lot more.