How can I learn about the Win32 API?

Question

I want to learn how to be able to use the Win32 API, since recently I've got a lot of tasks I need to do which requires functions from user32.dll, so I'm trying to learn and I Googled but the thing is: every tutorial there is about it, just tells you how to do a certain thing. like show a MessageBox through the Win32 API, but you can't actually learn Win32 framework.

So how do you actually learn it? How do you know all the functions? with managed libraries it's quite easy, especially with Visual Studio which provides IntelliSense, the Object Browser etc. but the Win32 API is so messy (at least from a C# developer standpoint).

The way I've been using it until now is just searching on Google for a task and seeing that it can be done with the Win32 API (I had no idea) and just copy the function and use it (and it's horrible for me, I feel I'm missing a lot of "power").

So, how can I learn it?

To be clear: I'm not interested in a book. as bad as it sounds I need this knowledge for a project and I just don't have the time to invest in a book. I did get my answer although.
Thank you all.

Answer 1

From MSDN you can find the WinAPI list: The following is a list of the reference content for the Windows application programming interface (API). http://msdn.microsoft.com/en-us/library/ff818516(v=vs.85).aspx

You can learn some stuff via Visual Basic Win API functions. Examples are very easy to follow and understand. Then you can translate the code to C#.

There Are 598 Visual Basic Windows API Functions in 55 Category http://www.ex-designz.net/api.asp