MFCThe Microsoft Foundation Class Library'

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MFC The Microsoft Foundation Class Library.

• MFC -1

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So what is this MFC Library?

• Most definitions will tell you that the MFC
  library is the class library for development of
  Microsoft ? Windows applications.
• So what is a class library?
• A "class library" is a set of standard classes
  (including properties and methods) for use in C
  program development.

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System Development?

• Although MFC was initially designed for
  application development.
• System Development is greatly simplified
• We need MFC to perform development for OLE and
  ActiveX in a realistic timescale!

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Justification for Use

• " they allow program developers to use some one
  else's code "
• The term reuse in theory equates to "makes
  development easier!"
• "MFC allows program developers to simplify the
  task of development of applications for windows
  in C, both by reuse of standard classes and by
  building basic skeleton code. "

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Why Use it ?

• The answer to this question lies in the idea
• MFC offer a standard set of classes to build the
  basic elements of a windows application
• it also includes the so called framework that
  builds a skeleton application.
• This framework takes away the tedium of the
  standard aspects of windows programming i.e.
  WinMain(..) and the basic WinProc(...).

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The Advantages

• Having a standard set of classes.
• to use the so called Class Wizards
• to assist in the basic framework development and
  also to act as a CASE tool as new methods data
  etc., are added to standard classes.

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An Example

• Using the application wizard you can specify a
  base system design including
• Multiple or single Document interfaces
• Tool Bars
• Status Bar
• Extensions on data manipulation
• Extensions to OLE design both container and server

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MFC Evolution

• It is important to look at the evolution of this
  particular class library.
• Originally MFC was no more than some very simple
  wrapper functionality around the basic window API
  calls.
• Now it reduces the complexity of API extensions
  such as MAPI,TAPI, OLE etc.

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CObject

• Serialisation the ability to load and save the
  object to /from structured permanent storage
• Runtime Class Information the class name its
  position in the hierarchy can be extracted at run
  time.

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CObject

• Diagnostic Output ability if in debug mode to
  use trace info in debug window
• Compatibility all objects must be a member of
  the MFC collection itself.

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Library itself can be broadly categorised into

• General purpose strings files, exceptions
  date/time and rectangles
• Visual Objects windows, device context, GDI
  functions and dialogues.
• Application architecture applications,
  documents (the data), views (on the data).
• Collections lists arrays etc.

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Library itself can be broadly categorised into

• OLE specific functionality
• ODBC specific functionality.

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Message Maps

• Each class that can receive messages or commands
  has its own "message map."
• The class uses message maps to connect messages
  and commands to their handler functions.

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A Typical message Map will have the form

• BEGIN_MESSAGE_MAP(CMyView, CView)
• //AFX_MSG_MAP (CMyView)
• ON_WM_MOUSE ACTIVATE()
• ON_COMMAND
• (ID_EDIT_CLEAR_ALL, OnEditClearAll)
• ON_UPDATE_COMMAND_UI
• (ID_EDIT_CLEAR_ALL, OnUpdateEditClearAll)
• //AFX_MSG_MAP

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CWinApp

• CWinApp class is the base class from which you
  always derive a windows application / system
  object.
• Each application that uses the MFC classes can
  only contain one object derived from CWinApp.
• CWinApp is declared at the global level.

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CWnd

• CWnd class provides the base functionality of all
  window classes.
• A CWnd object is distinct from a Windows window,
  but the two are tightly linked.
• The CWnd class and the message-map mechanism hide
  the WndProc function.

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CPaintDC

• The CPaintDC class is a device-context class
  derived from CDC..
• The CDC class defines a class of device-context
  objects. All drawing is accomplished through the
  member functions of a CDC object.
• Although this encapsulation aids readability it
  offers very little improvement on the basic GDI
  in the native API's.

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Document /Views

• Up to this point looking at the classes that are
  the basis of an application MFC can still be
  considered simply as wrappers for C around the
  basic 'C' API calls.
• CWinApp offers the control of the application.
• Start-up Execution Termination

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Document /Views

• The concept of documents and views builds this
  into a framework.
• The CDocument class provides the basic
  functionality for user-defined document classes.
• Users interact with a document through the CView
  object(s) associated with it.

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CFrameWnd

• 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.
• It is within these CFrameWnd that we will
  normally derive the CView onto our CDocument data.

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Some Typical Structures