CFrameWnd

CFrameWnd is a class in the Microsoft Foundation Classes (MFC) library that implements the frame window used by many MFC applications that follow the document/view architecture. It provides the standard window chrome, including a title bar, borders, and a client area, and acts as a container for the app’s menus, toolbars, and status bars. In an SDI (single document interface) or MDI (multiple document interface) setup, the frame window may host a view window or serve as the parent for multiple child frames managed by a CMDIFrameWnd.

CFrameWnd serves as the base class for higher-level frame classes such as CMDIFrameWnd and is commonly subclassed by developers to create the main or auxiliary frame windows of an application. It handles creation and initial setup of the frame, command routing, and update of UI elements in response to document state. The class coordinates with the document and view components to reflect the current document in the menu, toolbar, and status bar.

Typical customization points involve overriding window creation and initialization routines, such as PreCreateWindow to adjust window styles, OnCreate to set up UI elements like menus and toolbars, and OnCreateClient to create the client area that hosts the document/view hierarchy. CFrameWnd also participates in processes such as updating the frame title to reflect the active document and processing frame-level commands and accelerators.

In practice, applications generated from MFC templates often name their frame class CMainFrame and implement it as a subclass of CFrameWnd to tailor the overall window chrome and UI behavior.