This document provides an overview of basic Windows programming concepts, including: - Windows applications are event-driven and message-based, utilizing messages to communicate between components. System-defined and application-defined messages are described. - The typical steps for creating a window are outlined as registering the window class, creating the window, entering the message loop, and processing messages in the window procedure. - Resources, dynamic link libraries, the first Windows programs, and numeric identifiers are also briefly covered. Examples of common Windows messages like WM_PAINT and WM_DESTROY are given.

1. Win32 Programming Basic Concepts
Ping-Lun Liao

2. Outline
● Windows Message
● Resources
● Samples Demo

3. Windows and Applications
• Mechanisms to starts/terminate the application

4. Windows Application Components

5. Message Everywhere
● Event-Driven
● Message-Based Action

6. What is Windows Message?
● System-Defined Message
● Application-Defined Message

7. System-Defined Message
● The system sends or posts a system-
defined message when it communicates
with an application.
● It uses these messages to control the
operations of applications and to provide
input and other information for
applications to process.

8. System-Defined Message
● An application can also send or post syste
m-defined messages.
● Applications generally use these message
s to control the operation of control windo
ws created by using preregistered window
classes.

9. System-Defined Message

10. Application-Defined Message
● An application can create messages to be
used by its own windows or to
communicate with windows in other
processes.
● If an application creates its own messages,
the window procedure that receives them
must interpret the messages and provide
appropriate processing.

11. Steps For Creating A Window
● Step 1: Registering the Window Class
● Step 2: Creating the Window
● Step 3: The Message Loop
● Step 4: the Window Procedure

12. A Simple Window
● A Simple Window

13. Message Handling
● Message Loop
● Window Procedure

14. The Message Loop
• retrieves message from
the message queue
• sends message to the
Windows procedure
where the messages are
processed
• loops back and repeats
the procedure

15. The Message Loop
• Programs generally don't call window procedures directly.
• The window procedure is almost always called from Windows itself.
• A program can indirectly call its own window procedure by calling a function named
SendMessage().

16. The Message Loop
• Messages come
through in an orderly
and synchronized
manner.
• While processing one
message in a window
procedure, the
program will not be
suddenly interrupted
by another message.

17. Message Handling
WM_LBUTTONDOWNWM_DESTROYWM_PAINTWM_CREATE

18. The Message Loop
• Message loop retrieves a message from its
message queue
• Call DispatchMessage() to send the message off
to the window procedure
• DispatchMessage() does not return until the
window procedure has returned control back to
Windows.

19. The Message Loop

20. Windows Class and Registration

21. Windows Dialog Box

22. Windows Application Lifecycle

23. Resources
• Standard - icon, cursor, menu, dialog box,
bitmap, enhanced metafile, font, accelerator
table, message-table entry, string-table entry,
or version
• Custom - any kind of data that doesn't fall into
the previous category (for example a mp3 file
or a dictionary database).

24. Three dynamic-link libraries
● Kernel32.dll
– File I/O, System,…
● User32.dll
– User Interface…
● Gdi32.dll
– Fonts, Brushes…

25. First Windows Program
• Win32 API
● Win32ASM
● Visual C++
– MFC (Microsoft Foundation Classes)
● BCB (Borland C++ Builder)
– VCL (Visual Component Library)
● VB(???)
● .Net(C#, J#, C++, VB.NET)
– Windows Form
• 但是不論用那種方式，都是可以呼叫 Win32 API

26. Numeric identifiers
● In header file (always called resource.h)
● Example
– #define IDMAINMENU 300
– #define IDM_FILE_NEW 301
– #define IDM_FILE_OPEN 302
– #define IDM_FILE_SAVE 303
– #define IDM_FILE_EXIT 304
– #define IDM_HELP_ABOUT 305

27. Something about GetMessage
• Warning ： Because the return value can be
nonzero, zero, or -1, avoid code like this:
while (GetMessage( lpMsg, hWnd, 0, 0)) ...

28. Solution
BOOL bRet;
while( (bRet = GetMessage( &msg, NULL, 0, 0 )) != 0)
{
if (bRet == -1)
{
// handle the error and possibly exit
}
else
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}

29. Reference
● 深入淺出 MFC
● theForger's Win32 API Programming Tutorial