1. Introduction to Microsoft Windows MFC Programming: the Application/Window Approach
Lecture 4

2. MFC Windows Programming (App/Window Approach)
MFC stands for “The Microsoft Foundation Class Library”
Object oriented interface to windows.
A Hierarchy of C++ classes designed to facilitate Windows programming
An alternative to using Win32 API functions
A Visual C++ Windows application can use either Win32 API, MFC, or both
Lecture 4

3. Relationship between Windows MFC and Win32 API Programming
Lecture 4

4. Microsoft Foundation Classes
About 200 MFC classes (versus API functions )
Also called “Application Frame work”
Provide a framework upon which to build Windows applications
Encapsulate most of the Win32 API in a set of logically organized classes
MFC organizes the WIN32 API.
it groups related functionality into a class.
Wraps the windows API and windows objects with classes
Lecture 4

5. MFC Characteristics 1. Convenience of reusable code:
Many tasks common to all Windows apps are provided by MFC
Our programs can inherit and modify this functionality as needed
We don't need to recreate these tasks
2. Produce smaller executables:
Typically 1/3 the size of their API counterparts
Lecture 4

6. MFC Characteristics (contd)
3. Can lead to faster program development:
Make creation of windows application with C++ easy
Make access to Windows API features easier
4. MFC Programs must be written in C++
require the use of classes
Programmer must have good grasp of:
How classes are declared, instantiated, and used
Encapsulation
Inheritance
Polymorphism--virtual functions
Lecture 4

7. MFC Notations Classes names begins with ‘C’ CFrameWnd CView
Variable names begin with ‘m_’
m_pFrameWnd
Functions name begins with Afx
AfxMessageBox()
Lecture 4

8. MFC Class Hierarchy Two categories of classes CObject
Derived from CObject
Not Derived from CObject
CObject
At top of hierarchy ("Mother of all classes")
Provides features like:
Serialization
Streaming object’s persistent data to or from a storage medium (disk reading/writing)
Diagnostic & Debugging support
All its functionality is inherited by any classes derived from it
Lecture 4

9. Important Derived Classes—
CFile: Support for file operations
CDC: Encapsulates the device context (Graphical Drawing)
CGdiObject: Base class for various drawing objects (brushes, pens, fonts, etc.)
CMenu: Encapsulates menu management
Lecture 4

10. CCmdTarget: Encapsulates message passing process& is parent of:
CWnd: Encapsulates many important windows functions and data members
Example: m_hWnd stores the window’s handle
Base class all windows are derived from
Most common:
CFrameWindow: Can contain other windows
("normal" kind of window we've used)
CView: Encapsulates process of displaying and interacting with data
CDialog: Encapsulates dialog boxes
Lecture 4

11. CCmdTarget also parent of:
CWinThread: Defines a thread of execution and is the parent of:
CWinApp: Most important class dealt with in MFC applications:
Encapsulates an MFC application
Controls following aspects of Windows programs:
Startup, initialization, execution, shutdown
An application should have one CWinApp object
When instantiated, application begins to run
CDocument
Encapsulates the data associated with a program
Lecture 4

12. Not Derived from CObject
• Provide valuable additional services for MFC:
OLE Classes
Simple Data Type Classes
CImage
CRect
CString etc.
Synchronization classes
CSemaphore
CMutex
Lecture 4

13. Applications can also call API functions directly
Use Global Scope Resolution Operator, for
example:
::UpdateWindow(hWnd);
Usually more convenient to use MFC member functions
Lecture 4

14. Simplest MFC programs must contain two classes derived from hierarchy:
A Minimal MFC Program
Simplest MFC programs must contain two classes derived from hierarchy:
1. An application class derived from CWinApp
Defines the application
provides the message loop
Three common methods are
InitApplication();
InitInstance();
Run();
These methods created automatically when object is created.
Lecture 4

15. 2. A window class usually derived from CFrameWnd
Defines the application's main window
Referred as frame window
Tasks:
Creation of window
Management of window
It creates window and attach it to our program
These & other MFC classes brought in by using #include <Afxwin.h>
Lecture 4

16. #include <afxwin.h> class CMyApp : public CWinApp { public:
virtual BOOL InitInstance(); };
Lecture 4

17. class CMainFrame : public CFrameWnd { public: CMainFrame()
Create(NULL, "MFC Fundamentals"); } };
BOOL CMyApp ::InitInstance()
m_myWnd * CMainFrame ;
m_myWnd = new CMainFrame;
m_myWnd ->ShowWindow(SW_NORMAL);
m_pMainWnd= m_myWnd ;
return TRUE;
CMyApp a;
Lecture 4

18. Message Processing under MFC
Like API programs, MFC programs must handle messages from Windows
API mechanism: big switch/case statement
MFC mechanism: "message maps" (lookup tables)
Lecture 4

19. Messages in an application can be send in 2 ways
Directly
Queued
Message queue and message loop both are by passed
Windows directly call WndProc()
::SendMessage
::PostMessage
Lecture 4

20. System Defined Messages
Windows uses these messages
Each of the system defined messages has
unique numeric identifier
Corresponding identifier macro definition
System defined message macro prefix
BM Button control Messages
CB Combo Box control Messages
EM Edit Box control Messages
LB List Box control Messages
WM General Window Messages
Lecture 4

21. Message Handler
Message handler methods receive notification from the application object when some event occurs
Three types of messages processed in Message handler
Windows Messages
Control Notification Messages
Command Messages
Send by window to application
Starts with WM_*
WM_COMMAND exception
Lecture 4

22. Control Notification Messages
Send from child window
Control has no message queue and loop
Whatever activity notify directly to parent
Use message loop and queue of parent
Command Messages
Include WM_COMMAND
Notification from user interface object like
menu buttons
toolbar buttons
Lecture 4

23. Message Maps Mechanism for handling messaging with in a process
Object Oriented alternative to “switch-case” of window procedure
Table entries:
Message number
Pointer to a derived class member message-processing function
These are members of CWnd
You override the ones you want your app to respond to
Known as “Message handler”
Lecture 4

24. Message Mapping Programs must: Declaration Implementation
DECLARE_MESSAGE_MAP()
Implementation
BEGIN_MESSAGE_MAP( FC_Tutorial_Window, CFrameWnd)       ON_WM_LBUTTONDOWN() //Macro to map the left button click to the handler END_MESSAGE_MAP()
Lecture 4

25. Message Mapping Programs must:
Declare message-processing functions
e.g., OnWhatever() for WM_WHATEVER message
Map them to messages app is going to respond to
Mapping done by "message-mapping macros”
Bind a message to a handler function
e.g., ON_WM_WHATEVER()
Most MFC application windows use a window procedure, WndProc(), supplied by the library
Message maps enable library window procedure to find the function corresponding to the current msg.
Lecture 4

26. Lecture 4