CFrameWnd

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The CFrameWnd class provides the functionality of a Windows single document interface (SDI) overlapped or pop-up frame window, along with members for managing the window.

To create a useful frame window for your application, derive a class from CFrameWnd. Add member variables to the derived class to store data specific to your application. Implement message-handler member functions and a message map in the derived class to specify what happens when messages are directed to the window.

There are three ways to construct a frame window:

  • Directly construct it using Create.

  • Directly construct it using LoadFrame.

  • Indirectly construct it using a document template.

Before you call either Create or LoadFrame, you must construct the frame-window object on the heap using the C++ new operator. Before calling Create, you can also register a window class with the AfxRegisterWndClass global function to set the icon and class styles for the frame.

Use the Create member function to pass the frame’s creation parameters as immediate arguments.

LoadFrame requires fewer arguments than Create, and instead retrieves most of its default values from resources, including the frame’s caption, icon, accelerator table, and menu. To be accessible by LoadFrame, all these resources must have the same resource ID (for example, IDR_MAINFRAME).

When a CFrameWnd object contains views and documents, they are created indirectly by the framework instead of directly by the programmer. The CDocTemplate object orchestrates the creation of the frame, the creation of the containing views, and the connection of the views to the appropriate document. The parameters of the CDocTemplate constructor specify the CRuntimeClass of the three classes involved (document, frame, and view). A CRuntimeClass object is used by the framework to dynamically create new frames when specified by the user (for example, by using the File New command or the multiple document interface (MDI) Window New command).

A frame-window class derived from CFrameWnd must be declared with DECLARE_DYNCREATE in order for the above RUNTIME_CLASS mechanism to work correctly.

A CFrameWnd contains default implementations to perform the following functions of a main window in a typical application for Windows:

  • A CFrameWnd frame window keeps track of a currently active view that is independent of the Windows active window or the current input focus. When the frame is reactivated, the active view is notified by calling CView::OnActivateView.

  • Command messages and many common frame-notification messages, including those handled by the OnSetFocus, OnHScroll, and OnVScroll functions of CWnd, are delegated by a CFrameWnd frame window to the currently active view.

  • The currently active view (or currently active MDI child frame window in the case of an MDI frame) can determine the caption of the frame window. This feature can be disabled by turning off the FWS_ADDTOTITLE style bit of the frame window.

  • A CFrameWnd frame window manages the positioning of the control bars, views, and other child windows inside the frame window’s client area. A frame window also does idle-time updating of toolbar and other control-bar buttons. A CFrameWnd frame window also has default implementations of commands for toggling on and off the toolbar and status bar.

  • A CFrameWnd frame window manages the main menu bar. When a pop-up menu is displayed, the frame window uses the UPDATE_COMMAND_UI mechanism to determine which menu items should be enabled, disabled, or checked. When the user selects a menu item, the frame window updates the status bar with the message string for that command.

  • A CFrameWnd frame window has an optional accelerator table that automatically translates keyboard accelerators.

  • A CFrameWnd frame window has an optional help ID set with LoadFrame that is used for context-sensitive help. A frame window is the main orchestrator of semimodal states such as context-sensitive help (SHIFT+F1) and print-preview modes.

  • A CFrameWnd frame window will open a file dragged from the File Manager and dropped on the frame window. If a file extension is registered and associated with the application, the frame window responds to the dynamic data exchange (DDE) open request that occurs when the user opens a data file in the File Manager or when the ShellExecute Windows function is called.

  • If the frame window is the main application window (that is, CWinThread::m_pMainWnd), when the user closes the application, the frame window prompts the user to save any modified documents (for OnClose and OnQueryEndSession).

  • If the frame window is the main application window, the frame window is the context for running WinHelp. Closing the frame window will shut down WINHELP.EXE if it was launched for help for this application.

Do not use the C++ delete operator to destroy a frame window. Use CWnd::DestroyWindow instead. The CFrameWnd implementation of PostNcDestroy will delete the C++ object when the window is destroyed. When the user closes the frame window, the default OnClose handler will call DestroyWindow.

For more information on CFrameWnd, see in Visual C++ Programmer's Guide.

#include <afxwin.h>

Class Members |  Base Class |  Hierarchy Chart

See Also   CWnd, CMDIFrameWnd, CMDIChildWnd, CView, CDocTemplate, CRuntimeClass