1-1 Features of Windows applications

　　

　　

Main content: Describes the characteristics of Windows applications, and attaches some differences between messages and events//later in the classification of the font are used in Script 4 (14pt)

1. Object-oriented
<1> for Windows apps themselves, such as the Notepad interface,
Unlike the traditional console, it operates on objects such as windows, menus, and so on (the window is an object)
<2> object Popular is the part of the various specifications on the Windows application interface

<3> writing Windows programs want to be part of the job is to create objects and assign values to object properties
<4> object characteristics: With canonical morphology and operating mode

2. Message passing mechanism and event-driven mechanism
<1> Traditional MS-DOS programs are executed in the order of the program code
<2> Windows-based applications are message-based, event-driven,
but not controlled by the order of events, It is controlled by the occurrence of events, and this happens randomly
<3> The way Windows applications respond to user input mainly includes the message loop and event response mechanisms
example: the user clicks the left mouse button, Then in the message response mechanism will produce a click on the left mouse button this message,

3. Multitasking and multithreading
<1>windows is a multitasking operating system that can run multiple applications at the same time
　　

4. Multi-form input and output means
<1> Hardware Mode
Mouse, keyboard, scanner, handwriting board, etc.
<2> Software approach
Timer
　　

5. Device-Independent graphics output
<1>windows is a multi-window operating system that is managed by the operating system to unify the output of the screen
the system is output using GDI (graphics device Interface, graphic devices interface),
thus shielding the difference between the different devices
   
also attach the difference between the event and the message:
an event is an action-a user-triggered action.
a message is a message--information passed to the system.
   
The concept of events and messages is more confusing in computers, but essentially different:
   
events are triggered by the user (the person who operates the computer) and can only be triggered by the user, the operating system senses the event triggered by the user, and translates the event into a (specific) message queue that is sent to the program.
   
The emphasis here is:
It can be said that "the user triggered an event", not saying "the user triggered a message."
the user can only trigger events, and events can only be triggered by the user.
Once an event is generated, it is converted to a message by the operating system, so a message may be converted by an event (or generated by the operating system).
one message may produce another message, but a message must never produce an event--the time can only be triggered by the user.
   
Summary (event: The source of the message)
event: Can only be generated by the user through the input of the peripheral.
message: (There are three sources of generated messages)
(1) generated by the operating system.
(2) The event triggered by the user is converted.
(3) generated by another message.

1-1 Features of Windows applications