Resizing Controls in MFC

Question

I am writing a program which has two panes (via CSplitter), however I am having problems figuring out out to resize the controls in each frame. For simplicity,

Answer 1

When it comes to the window size changes, there are three window messages you may be interested in: ON_WM_SIZE(), ON_WM_SIZING(), and ON_WM_GETMINMAXINFO().

As the official docs says:

• ON_WM_SIZE whose message handler is ::OnSize() is triggered after the size of the CWnd has changed;
• ON_WM_SIZING whose message handler is ::OnSizing() is triggered when the size of the client area of the clipbord-viewer window has changed;
• ON_WM_GETMINMAXINFO whose message handler is ::OnGetMinMaxInfo() is triggered whenever the window needs to know the maximized position or dimensions , or the minimum or maximum tracking size.

If you want to restrict the size of the cwnd to some range, you may refer to message ON_WM_GETMINMAXINFO; and if you want to retrieve the size changes in real time, you may refer to the other two messages.

Answer 2

Others have pointed out that WM_SIZE is the message you should handle and resize the child controls at that point. WM_SIZE is sent after the resize has finished.

You might also want to handle the WM_SIZING message which gets sent while the resize is in progress. This will let you actively resize the child windows while the user is still dragging the mouse. Its not strictly necessary to handle WM_SIZING but it can provide a better user experience.