1、计算机专业毕业设计外文翻译Visual C+ MFC 简要介绍工 学 部 工学一部专 业 计算机科学与技术班 级学 号姓 名指导教师负责教师沈阳航空工业学院北方科技学院2008 年 7 月沈阳航空工 业学院北方科技学院毕业设计 (外文翻译)1 Introduction to MFC Programming with Visual C+ Version 6.x by Marshall Brain Visual C+ is much more than a compiler. It is a complete application development environment that, wh
2、en used as intended, lets you fully exploit the object oriented nature of C+ to create professional Windows applications. In order to take advantage of these features, you need to understand the C+ programming language. If you have never used C+, please turn to the C+ tutorials in the C/C+ Tutorials
3、 page for an introduction. You must then understand the Microsoft Foundation Class (MFC) hierarchy. This class hierarchy encapsulates the user interface portion of the Windows API, and makes it significantly easier to create Windows applications in an object oriented way. This hierarchy is available
4、 for and compatible with all versions of Windows. The code you create in MFC is extremely portable.These tutorials introduce the fundamental concepts and vocabulary behind MFC and event driven programming. In this tutorial you will enter, compile, and run a simple MFC program using Visual C+. Tutoti
5、al 2 provides a detailed explanation of the code used in Tutorial 1. Tutorial 3 discusses MFC controls and their customization. Tutorial 4 covers message maps, which let you handle events in MFC.What is the Microsoft Foundations Class Library? Lets say you want to create a Windows application. You m
6、ight, for example, need to create a specialized text or drawing editor, or a program that finds files on a large hard disk, or an application that lets a user visualize the interrelationships in a big data set. Where do you begin?A good starting place is the design of the user interface. First, deci
7、de what the user should be able to do with the program and then pick a set of user interface objects accordingly. The Windows user interface has a number of standard controls, such as buttons, menus, scroll bars, and lists, that are already familiar to Windows users. With this in mind, the programme
8、r must choose a set of controls and decide how they should be arranged on screen. A time-honored procedure is to make a rough sketch of the proposed user interface (by tradition on a napkin or the back of an envelope) and play with the elements until they feel right. For small projects, or for the e
9、arly prototyping phase of a larger project, this is sufficient.沈阳航空工 业学院北方科技学院毕业设计 (外文翻译)2 The next step is to implement the code. When creating a program for any Windows platform, the programmer has two choices: C or C+. With C, the programmer codes at the level of the Windows Application Program I
10、nterface (API). This interface consists of a collection of hundreds of C functions described in the Windows API Reference books. For Windows NT, the API is typically referred to as the “Win32 API,“ to distinguish it from the original 16-bit API of lower-level Windows products like Windows 3.1.Micros
11、oft also provides a C+ library that sits on top of any of the Windows APIs and makes the programmers job easier. Called the Microsoft Foundation Class library (MFC), this librarys primary advantage is efficiency. It greatly reduces the amount of code that must be written to create a Windows program.
12、 It also provides all the advantages normally found in C+ programming, such as inheritance and encapsulation. MFC is portable, so that, for example, code created under Windows 3.1 can move to Windows NT or Windows 95 very easily. MFC is therefore the preferred method for developing Windows applicati
13、ons and will be used throughout these tutorials.When you use MFC, you write code that creates the necessary user interface controls and customizes their appearance. You also write code that responds when the user manipulates these controls. For example, if the user clicks a button, you want to have
14、code in place that responds appropriately. It is this sort of event-handling code that will form the bulk of any application. Once the application responds correctly to all of the available controls, it is finished.You can see from this discussion that the creation of a Windows program is a straight
15、forward process when using MFC. The goal of these tutorials is to fill in the details and to show the techniques you can use to create professional applications as quickly as possible. The Visual C+ application development environment is specifically tuned to MFC, so by learning MFC and Visual C+ to
16、gether you can significantly increase your power as an application developer.Windows Vocabulary The vocabulary used to talk about user interface features and software development in Windows is basic but unique. Here we review a few definitions to make discussion easier for those who are new to the e
17、nvironment.Windows applications use several standard user controls:Static text labels 沈阳航空工 业学院北方科技学院毕业设计 (外文翻译)3 Push buttons List boxes Combo boxes (a more advanced form of list) Radio boxes Check boxes Editable text areas (single and multi-line) Scroll bars You can create these controls either in
18、 code or through a “resource editor“ that can create dialogs and the controls inside of them. In this set of tutorials we will examine how to create them in code. See the tutorials on the AppWizard and ClassWizard for an introduction to the resource editor for dialogs.Windows supports several types
19、of application windows. A typical application will live inside a “frame window“. A frame window is a fully featured main window that the user can re-size, minimize, maximize to fill the screen, and so on. Windows also supports two types of dialog boxes: modal and modeless. A modal dialog box, once o
20、n the screen, blocks input to the rest of the application until it is answered. A modeless dialog box can appear at the same time as the application and seems to “float above“ it to keep from being overlaid.Most simple Windows applications use a Single Document Interface, or SDI, frame. The Clock, P
21、IF editor, and Notepad are examples of SDI applications. Windows also provides an organizing scheme called the Multiple Document Interface, or MDI for more complicated applications. The MDI system allows the user to view multiple documents at the same time within a single instance of an application.
22、 For example, a text editor might allow the user to open multiple files simultaneously. When implemented with MDI, the application presents a large application window that can hold multiple sub-windows, each containing a document. The single main menu is held by the main application window and it ap
23、plies to the top-most window held within the MDI frame. Individual windows can be iconified or expanded as desired within the MDI frame, or the entire MDI frame can be minimized into a single icon on the desktop. The MDI interface gives the impression of a second desktop out on the desktop, and it g
24、oes a long way towards organizing and removing window clutter.Each application that you create will use its own unique set of controls, its own menu 沈阳航空工 业学院北方科技学院毕业设计 (外文翻译)4 structure, and its own dialog boxes. A great deal of the effort that goes into creating any good application interface lies
25、 in the choice and organization of these interface objects. Visual C+, along with its resource editors, makes the creation and customization of these interface objects extremely easy.Event-driven Software and Vocabulary All window-based GUIs contain the same basic elements and all operate in the sam
26、e way. On screen the user sees a group of windows, each of which contains controls, icons, objects and such that are manipulated with the mouse or the keyboard. The interface objects seen by the user are the same from system to system: push buttons, scroll bars, icons, dialog boxes, pull down menus,
27、 etc. These interface objects all work the same way, although some have minor differences in their “look and feel.“ For example, scroll bars look slightly different as you move from Windows to the Mac to Motif, but they all do the same thing.From a programmers standpoint, the systems are all similar
28、 in concept, although they differ radically in their specifics. To create a GUI program, the programmer first puts all of the needed user interface controls into a window. For example, if the programmer is trying to create a simple program such as a Fahrenheit to Celsius converter, then the programm
29、er selects user interface objects appropriate to the task and displays them on screen. In this example, the programmer might let the user enter a temperature in an editable text area, display the converted temperature in another un-editable text area, and let the user exit the program by clicking on
30、 a push-button labeled “quit“.As the user manipulates the applications controls, the program must respond appropriately. The responses are determined by the users actions on the different controls using the mouse and the keyboard. Each user interface object on the screen will respond to events diffe
31、rently. For example, if the user clicks the Quit button, the button must update the screen appropriately, highlighting itself as necessary. Then the program must respond by quitting. Normally the button manages its appearance itself, and the program in some way receives a message from the button tha
32、t says, “The quit button was pressed. Do something about it.“ The program responds by exiting.Windows follows this same general pattern. In a typical application you will create a main window and place inside it different user interface controls. These controls are often referred to as child windows
33、-each control is like a smaller and more specialized sub-沈阳航空工 业学院北方科技学院毕业设计 (外文翻译)5 window inside the main application window. As the application programmer, you manipulate the controls by sending messages via function calls, and they respond to user actions by sending messages back to your code.If
34、 you have never done any “event-driven“ programming, then all of this may seem foreign to you. However, the event-driven style of programming is easy to understand. The exact details depend on the system and the level at which you are interfacing with it, but the basic concepts are similar. In an ev
35、ent-driven interface, the application paints several (or many) user interface objects such as buttons, text areas, and menus onto the screen. Now the application waits-typically in a piece of code called an event loop-for the user to do something. The user can do anything to any of the objects on sc
36、reen using either the mouse or the keyboard. The user might click one of the buttons, for example. The mouse click is called an event. Event driven systems define events for user actions such as mouse clicks and keystrokes, as well as for system activities such as screen updating.At the lowest level
37、 of abstraction, you have to respond to each event in a fair amount of detail. This is the case when you are writing normal C code directly to the API. In such a scenario, you receive the mouse-click event in some sort of structure. Code in your event loop looks at different fields in the structure,
38、 determines which user interface object was affected, perhaps highlights the object in some way to give the user visual feedback, and then performs the appropriate action for that object and event. When there are many objects on the screen the application becomes very large. It can take quite a bit
39、of code simply to figure out which object was clicked and what to do about it.Fortunately, you can work at a much higher level of abstraction. In MFC, almost all these low-level implementation details are handled for you. If you want to place a user interface object on the screen, you create it with
40、 two lines of code. If the user clicks on a button, the button does everything needed to update its appearance on the screen and then calls a pre-arranged function in your program. This function contains the code that implements the appropriate action for the button. MFC handles all the details for
41、you: You create the button and tell it about a specific handler function, and it calls your function when the user presses it. Tutorial 4 shows you how to handle events using message mapsAn Example One of the best ways to begin understanding the structure and style of a typical MFC program is to ent
42、er, compile, and run a small example. The listing below contains a simple 沈阳航空工 业学院北方科技学院毕业设计 (外文翻译)6 “hello world“ program. If this is the first time youve seen this sort of program, it probably will not make a lot of sense initially. Dont worry about that. We will examine the code in detail in the
43、 next tutorial. For now, the goal is to use the Visual C+ environment to create, compile and execute this simple program./hello.cpp#include / Declare the application classclass CHelloApp : public CWinApppublic:virtual BOOL InitInstance();/ Create an instance of the application classCHelloApp HelloAp
44、p;/ Declare the main window classclass CHelloWindow : public CFrameWndCStatic* cs;public:CHelloWindow();/ The InitInstance function is called each/ time the application first executes.BOOL CHelloApp:InitInstance()m_pMainWnd = new CHelloWindow();m_pMainWnd-ShowWindow(m_nCmdShow);m_pMainWnd-UpdateWind
45、ow();return TRUE;/ The constructor for the window classCHelloWindow:CHelloWindow()沈阳航空工 业学院北方科技学院毕业设计 (外文翻译)7 / Create the window itselfCreate(NULL,“Hello World!“,WS_OVERLAPPEDWINDOW,CRect(0,0,200,200);/ Create a static labelcs = new CStatic();cs-Create(“hello world“,WS_CHILD|WS_VISIBLE|SS_CENTER,CR
46、ect(50,80,150,150),this);This small program does three things. First, it creates an “application object.“ Every MFC program you write will have a single application object that handles the initialization details of MFC and Windows. Next, the application creates a single window on the screen to act a
47、s the main application window. Finally, inside that window the application creates a single static text label containing the words “hello world“. We will look at this program in detail in the next tutorial to gain a complete understanding of its structure.The steps necessary to enter and compile thi
48、s program are straightforward. If you have not yet installed Visual C+ on your machine, do so now. You will have the option of creating standard and custom installations. For the purposes of these tutorials a standard installation is suitable and after answering two or three simple questions the res
49、t of the installation is quick and painless.Start VC+ by double clicking on its icon in the Visual C+ group of the Program Manager. If you have just installed the product, you will see an empty window with a menu bar. If VC+ has been used before on this machine, it is possible for it to come up in several different states because VC+ remembers and automatically reopens the project and files in use the last time it exited. What we want right now is a state where it has no project or code loaded. If the program starts with a dialog that
