Programming Microsoft Visual C++

The toolbar is an object of class CToolBar, and the status bar is an object of class CStatusBar. Both these classes are derived from class CControlBar, which is itself derived from CWnd. The CControlBar class supports control bar windows that are positioned inside frame windows. These control bar windows resize and reposition themselves as the parent frame moves and changes size. The application framework takes care of the construction, window creation, and destruction of the control bar objects. AppWizard generates control bar code for its derived frame class located in the files MainFrm.cpp and MainFrm.h.

In a typical SDI application, a CToolBar object occupies the top portion of the CMainFrame client area and a CStatusBar object occupies the bottom portion. The view occupies the remaining (middle) part of the frame.

Beginning with Microsoft Foundation Class (MFC) Library version 4.0, the toolbar has been built around the toolbar common control that first became available with Microsoft Windows 95. Thus the toolbar is fully dockable. The programming interface is much the same as it was in earlier versions of the MFC library, however. The button images are easy to work with because a special resource type is supported by the resource editor. The old global buttons array is gone.

Assuming that AppWizard has generated the control bar code for your application, the user can enable and disable the toolbar and the status bar individually by choosing commands from the application's View menu. When a control bar is disabled, it disappears and the view size is recalculated. Apart from the common behavior just described, toolbar and status bar objects operate independently of each other and have rather different characteristics.

In Visual C++ 6.0, a new MFC toolbar was introduced called the rebar. The rebar is based on the controls that come as part of Microsoft Internet Explorer 4.0 and provides a Microsoft Internet Explorer-style "sliding" toolbar. We will cover this later in this chapter.