My objective is to have a CToolBar derivative which has a single control on it (a CMFCShellTreeCtrl).
Something like:
class CFileTreeBar : public CToolBar
Whenever it is asked to compute its size, I want to respond that it is either a fixed minimum, or the size of the client area of the dock bar to which it is docked. In other words, it should consume the entire height of the dock bar + a fixed width (this is being docked on the left – exactly as Explorer lays out its folder tree on the left).
Hence, in CFileTreeBar::CalcFixedLayout it responds with height based on GetParent()->GetWindowRect(rect), and a width of 250pix.
Then in OnSize, the CFileTreeBar resizes its CMFCShellTreeCtrl to consume our client rect (maximizes our only control).
This works beautifully for when the control bar is initially displayed. And it works great when resizing the window by dragging a corner. The CaclFixedLayout returns a different value from its previous value (because the window size changed) and so it computes that it should consume the entire vertical space and eventually I get an WM_SIZE message telling my control bar to resize, which causes me to update the size of the CMFCShellTreeCtrl.
Where I am struggling is when hitting “maximize” button on the CFrameWnd. In this case, for reasons I don’t really understand, the CalcFixedLayout is called but the dock bar has its old size (it hasn’t been updated to the new sized based on being maximized yet). This causes my code to respond that the size should be the same as it was previously – which causes MFC frame work to not issue a resize (we’re already the size we claim we need to be).
Hence, a moment later the dock bar is expanded to consume the whole vertical space, but my control bar and its underlying shell tree are not resized – but left behind with the stale size.
The problem happens also when going from maximized to restored. At that point the call to CalcFixedLayout indicates that we should be as tall as the maximized window (its current size), and now the frame work kicks off the resizing code which ends up making us larger than the dock bar (once it is resized down to restored size), and we disappear below the bottom of the dock bar (clipped by it’s maximum vertical extent).
Questions
- Is there a good tutorial or white paper showing the overview of how dockbars and control bars are supposed to interact in MFC? i.e. a complete description of how this frame work is supposed to hang together properly? Understanding how these pieces fit together and are intended to work coherently would go a long way towards avoiding hacking it to work, allowing me to write something round to fit the round hole, so to speak.
- Is there an example project similar to this that anyone is aware of? Having to figure this junk out is incredibly time consuming – if there is an example somewhere which does this, then that would be great…
Dockable and resizable toolbar is quite complicated to code, there is one in codeproject which is quite good. You can study the source code to see how the author do it.
http://www.codeproject.com/Articles/6/CSizingControlBar-a-resizable-control-bar