Microsoft Foundation Classes

1. Microsoft Foundation Classes

2. What is MFC? • Set of C++ classes written by MS • Simplifies writing complex programs • Covers many areas: • GUI • I/O • O/S interfaces • ActiveX • Framework for IE extensions • Component of Windows

3. Why Use MFC? • Faster development • More code is reusable • Many common tasks are "built-in" • Winmain, WndProc • Smaller executable • Uses all the C++ paradigms • Inheritance, polymorphism, etc.

4. MFC class categories • CObject – the root class • Application architecture classes • Window, dialog, control • Drawing, printing • Datatypes • Array, list, map • File & DB • Internet & networking • OLE • Debugging Used in this course

5. Cobject • Think of it as the "master" class • Serialization • Stream data to/from devices (disks) • Runtime class info • Debugging • Some derived classes • Cmenu (menus & menu mgmt.) • CDC (device context & drawing) • CGdiObject (drawing devices – brushes, etc)

6. Related info • MFC class hierarchy chart • Macros & global variables • WndProc (Win32API) buried in MFC library • Message Maps • Names of events • Handler functions for those events • E.g.; ON_WM_MOVE for CMainFrame::OnMove • ON_WM_MOVE pre-defined constant • OnMove pre-defined fn in the CMainFrame class

7. WIn32API vs MFC Message handling Window gets moved Window gets moved WndProc() case WM_MOVE: movefn(); CMainFrame::OnMove Win32API MFC

8. Parts of a basic MFC Program - 1MyWinApp.h #include <afxwin.h> class CMyWinApp : public CWinApp { public: virtual BOOL InitInstance(); };

9. Parts of a basic MFC Program – 2MainFrame.h #include <afxwin.h> class CMainFrame : public CFrameWnd { private: // variables known to all CMainFrame members public: // define the prototypes for functions to handle window events CMainFrame(); // class constructor // prototypesfor members named in the MESSAGE MAP // The MESSAGE MAP is implemented in MainFrame.cpp //afx_msgint OnCreate(LPCREATESTRUCT lpCreateStruct); //afx_msg void OnShowWindow(BOOL bShow, UINT nStatus); afx_msgvoid OnMove(int x, int y); afx_msg void OnPaint(); // msghndlr for WM_PAINT event void common(CWnd* wptr); DECLARE_MESSAGE_MAP(); }; // note: the "afx_msg" prefix is pre-VS 2005 and is #defined as empty

10. Parts of a basic MFC Program – 3 // Main.cpp #include "MyWinApp.h" CMyWinAppMyApplication;

11. Parts of a basic MFC Program – 4// MyWinApp.cpp // create the window frame & display it #include "MyWinApp.h" #include "MainFrame.h" BOOL CMyWinApp::InitInstance() { CMainFrame *pFrame; pFrame= new CMainFrame; m_pMainWnd = pFrame; pFrame->ShowWindow(SW_SHOW); pFrame->UpdateWindow(); return TRUE; }

12. Parts of a basic MFC Program – 5aMainFrame.cpp • This is where all the real work gets done #include "MainFrame.h" // Define the messages we will respond to and create the window BEGIN_MESSAGE_MAP (CMainFrame, CFrameWnd) // classname, base class //ON_WM_CREATE() //ON_WM_SHOWWINDOW() //ON_WM_ACTIVATE() ON_WM_MOVE() ON_WM_PAINT() END_MESSAGE_MAP()

13. Parts of a basic MFC Program – 5bMainFrame.cpp – part 2 CMainFrame::CMainFrame()// Explicit constructor { CString title = "DJ's WIndow"; Create (NULL /* classname*/, title, WS_OVERLAPPEDWINDOW, CRect (0, 0, 670, 300), NULL, /* parent window ptr*/ 0, /* ID */ NULL /* create context ptr - onlyif overriding the context */ ); }

14. Parts of a basic MFC Program – 5c void CMainFrame::OnPaint() {CPaintDC dc(this);// "this" is a handle for current window // dc is the "device context" for the window dc.TextOut(x, y, "hello"); // works for printers or displays common (this); // call common code and pass the context } void CMainFrame::OnMove() { } void CMainFrame::common (CWnd * wptr) { // have the window ptr (wptr), but not always using it }

15. Window, Dialog & Control classes • Frame Window • CFrameWnd, CMenu • View – • Represent client area of a frame • Show data, accept input • Cview, CScrollView, form & record, control • Dialog box (modal, modeless) • Cdialog, CDataExchange • Control – • Attached to CFrameWnd or CMiniFrameWnd • Static, text, number, button, list, toolbar, misc • Control bar

16. CFrameWnd • Framework for a single-document interface • Usage • Derive a class using CFrameWnd::Create • Add member variables for your data • Implement message handlers • Define a message map • Specifies actions when the window gets a msg

17. Dialog boxes • Modal • Requires user interaction • Blocks program operation until action completed • Mode errors can be caused by: • Caps-lock or Insert key • Focus stealing (user types but nothing happens) • Modeless • No interaction required (e.g.; toolbar) • Note: this happens a lot in Unix/Linux editor, "vi", because mode indicator can be "off".

18. Views • Represent the client area of a frame window • Associated with document class & CFrameWnd • 2 types of document views • Cview- base class for app-specific views • CScrollView- base class for scrollable data • CFormView, CRecordView, CHtmlEditView • Control views • CCrtlView, CEditView, CCListView, CTreeView

19. GetWindowRect • Win32API version BOOL WINAPI GetWindowRect ( HWND hWnd,  LPRECT lpRect ); note: TWO parameters, lpRect is a struct • MFC version: voidGetWindowRect ( LPRECT lpRect  ) const; note: one parameter, lpRect is a class (a Crect object)

20. Document/View Architecture • Display of data should be independent of the data • May need to have different ways to look at the data • CDocument class holds the data • CView manages display and UI • 2 kinds of apps: • Single Document Interface • Multiple Document Interface

21. View • Display of the data & a way to display it • Frame window: contains a view of the data • Multiple views possible • But only ONE doc per View

22. tips • SDI application • One frame window derived from class CFrameWnd. • This window is both: • main frame window • and document frame window. • MDI application, the main frame window is derived from class CMDIFrameWnd, and the document frame windows, which are MDI child windows, are derived from class CMDIChildWnd.