How to make multiple windows using Win32 API

Question

I see plenty of tutorials and articles showing me how to make a simple windows program, which is great but none of them show me how to make multiple windows.

Right now I have working code that creates and draws a layered window and I can blit stuff using GDI to draw anything I want on it, drag it around, even make it transparent, etc.

But I wanted a second rectangular area that I can draw to, drag around, etc. In other words, a second window. Probably want it to be a child window. Question is, how do I make it?

Also, if anybody knows any good resources (online preferably) like articles or tutorials for window management in the Windows API, please share.

Answer 1

It sounds like you want a Multiple Document Interface. Here is an example of one:

http://www.codeproject.com/KB/winsdk/Sigma.aspx

Answer 2

You can hit CreateWindow() more than once if you want. The message loop in your WinMain will pass events to all the windows that WinMain creates. You can even create two overlapped windows and set the parent window of the 2nd one to be the handle of the 1st one if you want.

Answer 3

You can create as many windows as you want using CreateWindow/CreateWindowEx, with the relationship between them as you desire (owner/child).

You can make a window "owned" by other with:

SetWindowLongPtr(hwnd, GWLP_HWNDPARENT, (LONG_PTR) hwndParent);

To convert a window to child, use SetParent.

Note that the SetWindowLongPtr call with GWLP_HWNDPARENT does not behave as SetParent (MSDN is wrong on this I think). GWLP_HWNDPARENT does not convert a window to "child", but to "owned".