MFC, ATL, and WFC Is MFC Dead?

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1 MFC, ATL, and WFC Is MFC Dead? MFC, ATL, and WFC Is MFC Dead? Ever since Microsoft released the Active Template Library (ATL) as part of Visual C++, Windows developers have speculated that the Microsoft Foundation Class Library (MFC) was no longer "en vogue" at Microsoft and that future efforts would focus on newer libraries such as ATL. Recently, Microsoft released another class library, Windows Foundation Classes (WFC), for Java Windows developers, which has unfortunately helped to fan the rumors that "MFC is dead." The rumors of MFC's demise are definitely premature. Visual C has added significant functionality to MFC and ATL in parallel, which indicates that both libraries will receive equal attention moving forward. Part of the problem is that the design goals of each library are sometimes not clearly stated and therefore are not clearly understood by the Visual C++ developer. MFC is designed to be a great class library for creating graphically rich, sophisticated Windows applications. ATL is designed to make it easy to create extremely lightweight COM objects and ActiveX controls. Each of these design goals has resulted in a different library to empower the developer. Another common misconception is that MFC and ATL are mutually exclusive. This is definitely not the case! In fact, it is very easy to create ATL-based COM objects that use MFC. The only issue is that since many developers choose ATL for its lightweight nature, using MFC, which is feature-rich and "heavy," seems to contradict the reason for choosing ATL. While this might be the case for some developers, it doesn't make ATL and MFC mutually exclusive. While ATL does not replace MFC, we do think it is an important part of Visual C++, so in this edition of Programming Microsoft Visual C++ we have added two chapters that cover the ATL class libraries.

2 C++ vs. Java C++ vs. Java In the last couple of years, there has been a great deal of interest in the Java programming language. Why should you choose C++ over Java? In the first place, a compiled program will always be faster than an interpreted program. Think about a high-performance spreadsheet program with cell formulas and macros. Now imagine the Java virtual machine interpreting the code that, in turn, interprets the formulas and macros. Not pretty, is it? With just-in-time compilation, it's necessary to compile the program every time you load it. Will that code be as good as the optimized output from a C++ compiler? Execution speed is one factor; access to the operating system is another. For security reasons, Java applets can't perform such tasks as writing to disk and accessing serial ports. In order to be platform-independent, Java application programs are limited to the "lowest common denominator" of operating system features. A C++ program for Microsoft Windows is more flexible because it can call any Win32 function at any time. Java will be an important language, but we believe it's just another language, not a revolution. If you need an Internet applet or a truly platform-independent application, choose Java. If you need efficiency and flexibility, choose C++.

3 Who Can Use This Book Who Can Use This Book The product name "Visual C++" misleads some people. They think they've bought a pure visual programming system similar to Microsoft Visual Basic, and for the first few days the illusion persists. However, people soon learn that they must actually read and write C++ code. The Visual C++ wizards save time and improve accuracy, but programmers must understand the code that the wizards generate and, ultimately, the structure of the MFC library and the inner workings of the Windows operating system. Visual C++, with its sophisticated application framework, is for professional programmers, and so is this book. We assume that you're proficient in the C language you can write an if statement without consulting the manual. And we assume that you've been exposed to the C++ language you've at least taken a course or read a book, but maybe you haven't written much code. Compare learning C++ to learning the French language. You can study French in school, but you won't be able to speak fluently unless you go to France and start talking to people. Reading this book is like taking your trip to France! We won't assume, however, that you already know Windows programming. We're sure that proficient C programmers can learn Windows the MFC way. It's more important to know C++ than it is to know the Win32 application programming interface (API). You should, however, know how to run Windows and Windows-based applications. What if you're already experienced with the Win32 API or with the MFC library? There's something in this book for you too. First you'll get some help making the transition to Win32 programming. Then you'll learn about new features such as Data Access Objects (DAO), ActiveX control container support, and the controls introduced with Windows 95. If you haven't already figured out the Component Object Model (COM), this book presents some important theory that will get you started on understanding ActiveX Controls. You'll also learn about the ATL class library, the new Microsoft Internet Explorer 4.0 common controls, and OLE/DB database programming. Finally, you'll learn C++ programming for the Internet (including the hot new topic Dynamic HTML). We've even included coverage on how to make your Visual C++ programs work on the new Windows CE operating system.

4 What's Not Covered What's Not Covered It's not possible to cover every aspect of Windows-based programming in a single book. We exclude topics that depend on special-purpose hardware and software, such as MAPI, TAPI, and communications port access. We do cover using ActiveX controls in an application, but we'll defer the subject of writing ActiveX controls to Adam Denning and his ActiveX Controls Inside Out (Microsoft Press, 1997). We get you started with 32-bit memory management, DLL theory, and multithreaded programming techniques, but you need to get the third edition of Jeffrey Richter's Advanced Windows (Microsoft Press, 1997) if you're serious about these subjects. Another useful book is MFC Internals by George Shepherd and Scot Wingo (Addison-Wesley, 1996).

5 How to Use This Book How to Use This Book When you're starting with Visual C++, you can use this book as a tutorial by going through it sequentially. Later you can use it as a reference by looking up topics in the table of contents or in the index. Because of the tight interrelationships among many application framework elements, it wasn't possible to cleanly isolate each concept in its own chapter, so the book really isn't an encyclopedia. When you use this book, you'll definitely want to keep the online help available for looking up classes and member functions. If you're experienced with the Win16 version of Visual C++, scan Part I for an overview of new features. Then skip the first three chapters of Part II, but read Chapters 6 through 12, which cover elements specific to Win32.

6 The Organization of This Book The Organization of This Book As the table of contents shows, this book has six parts and an appendix section. Part I: Windows, Visual C++, and Application Framework Fundamentals In this part, we try to strike a balance between abstract theory and practical application. After a quick review of Win32 and the Visual C++ components, you'll be introduced, in a gentle way, to the MFC application framework and the document-view architecture. You'll look at a simple "Hello, world!" program, built with the MFC library classes, that requires only 30 lines of code. Part II: The MFC Library View Class The MFC library documentation presents all the application framework elements in quick succession, with the assumption that you know the original Windows API. In Part II, you're confined to one major application framework component the view, which is really a window. You'll learn here what experienced Windows programmers know already, but in the context of C++ and the MFC library classes. You'll use the Visual C++ tools that eliminate much of the coding drudgery that early Windows programmers had to endure. Part II covers a lot of territory, including graphics programming with bitmaps, dialog data exchange, ActiveX control usage, 32-bit memory management, and multithreaded programming. The exercises will help you to write reasonably sophisticated Windows-based programs, but those programs won't take advantage of the advanced application framework features. Part III: The Document-View Architecture This part introduces the real core of application framework programming the document-view architecture. You'll learn what a document is (something much more general than a word processing document), and you'll see how to connect the document to the view that you studied in Part II. You'll be amazed, once you have written a document class, at how the MFC library simplifies file I/O and printing. Along the way, you'll learn about command message processing, toolbars and status bars, splitter frames, and context-sensitive help. You'll also be introduced to the Multiple Document Interface (MDI), the current standard for Windows-based applications. Part III also contains a discussion of dynamic link libraries (DLLs) written with the MFC library. You'll learn the distinction between an extension DLL and a regular DLL. If you're used to Win16 DLLs, you'll notice some changes in the move to Win32. Part IV: ActiveX: COM, Automation, and OLE COM by itself deserves more than one book. Part IV will get you started in learning fundamental COM theory from the MFC point of view. You'll progress to Automation, which is the link between C++ and Visual Basic for Applications (VBA). You'll also become familiar with uniform data transfer and structured storage, and you'll learn the basics of compound documents and embedded objects. Part V: Database Management Windows-based programs often need access to information in large databases. Visual C++ now supports two separate database management options: Open Database Connectivity (ODBC) and Data Access Objects (DAO). Part V offers a chapter on each option. You'll learn about the extensive MFC and wizard support for both options, and you'll see the differences between and similarities of ODBC and DAO. We'll also cover a new data access technology, OLE/DB, which is supported by ATL OLE/DB consumer and providers. Part VI: Programming for the Internet This part starts with a technical Internet tutorial that covers the TCP/IP protocol plus the Winsock and WinInet APIs. You'll learn how to write C++ server and client programs for the Internet and the intranet, you'll learn how to write ISAPI DLLs that extend the Microsoft Internet Information Server, and you'll learn how to program for Dynamic HTML. We've also included coverage on Windows CE in this section. Appendixes Appendix A contains a list of message map macros and their corresponding handler function prototypes. ClassWizard usually generates this code for you, but sometimes you must make manual entries. Appendix B offers a description of the MFC application framework's runtime class information and dynamic creation system. This is independent of the RTTI (runtime type information) feature that is now a part of ANSI C++.

7 Win32 vs. Win16 Win32 vs. Win16 Lots of old computers out there are still running Windows 3.1. However, there's not much point in spending money writing new programs for obsolete technology. This edition of Programming Microsoft Visual C++ is about 32-bit programming for Microsoft Windows 95, Microsoft Windows 98, and Microsoft Windows NT using the Win32 API. If you really need to do 16-bit programming, find an old copy of the second edition of this book.

8 Windows 95 and Windows 98 vs. Windows NT Windows 95 and Windows 98 vs. Windows NT Visual C++ version 6.0 requires either Windows 95, Windows 98, or Windows NT version 4.0 or later, all of which have the same user interface. We recommend that you use Windows NT as your development platform because of its stability you can often go for months without rebooting your computer. If you use only the MFC programming interface, your compiled programs will run under Windows 95, Windows 98, and Windows NT, but a program can include Win32 calls that use specific Windows 98 or Windows NT features.

9 Going Further with Windows: The "For Win32 Programmers" Sidebars Going Further with Windows: The "For Win32 Programmers" Sidebars This book can't offer the kind of detail, tricks, and hidden features found in the newer, specialized books on Win32. Most of those books are written from the point of view of a C-language programmer: in order to use them, you'll have to understand the underlying Win32 API and its relationship to the MFC library. In addition, you'll need to know about the Windows message dispatch mechanism and the role of window classes. This book's "For Win32 Programmers" sidebars, scattered throughout the text, help you make the connection to low-level programming for Windows. These specially formatted boxes help experienced C programmers relate new MFC library concepts to principles they're already familiar with. If you're unfamiliar with low-level programming, you should skip these notes the first time through, but you should read them on your second pass through the book. Even though you may never write a low-level Windows-based program with a WinMain function, for example, you eventually need to know how the Windows operating system interacts with your program.

10 Using the Companion CD-ROM Using the Companion CD-ROM The companion CD-ROM bound inside the back cover of this book contains the source code files for all the sample programs. The executable program files are included, so you won't have to build the samples that you're interested in. To install the companion CD-ROM's files, insert the disc in your CD-ROM drive and run the Setup program. Follow the on-screen instructions. The Setup program copies about 30 MB of files to your hard disk. If you prefer, you can manually install only the files for individual projects. Simply tree-copy the corresponding subdirectories from the CD-ROM to c:\vcpp32. Because each project is self-contained, no additional files from other projects are needed. (You'll need to remove the read-only attribute from these files if you copy them using Windows Explorer or File Manager.) Many of the files on the companion CD-ROM have long filenames. If you use Windows 95 and your CD-ROM drive uses a real-mode driver, you'll see truncated names for these files and you might not see all of the files or directories. The Setup program will still work correctly, however, by copying files from a special \SETUP directory on the CD-ROM and renaming them with their proper long filenames. You can then browse the files on your hard disk. Alternatively, you can browse the files using the 8.3 aliases in the \SETUP directory on the CD-ROM. With a conventional C-language program using the Windows API, the source code files tell the whole story. With the MFC library application framework, things are not so simple. AppWizard generates much of the C++ code, and the resources originate in the resource editors. The examples in the early chapters of this book include step-bystep instructions for using the tools to generate and customize the source code files. You'd be well advised to walk through those instructions for the first few examples; there's very little code to type. For the middle chapters, use the code from the companion CD-ROM but read through the steps in order to appreciate the role of the resource editors and the wizards. For the final chapters, not all the source code is listed. You'll need to examine the companion CD-ROM's files for those examples. For Win32 Programmers: Unicode Until recently, Windows-based programs have used only the ANSI character set, which consists of 256 single-byte characters. Developers targeting the Asian software market are moving to the Unicode character set, which consists of 65,536 characters, each 2 bytes (wide). A third option, the double-byte character set (DBCS), includes both 1-byte characters and 2-byte characters, but DBCS is falling out of favor. The MFC library and the runtime library both support Unicode applications. If you define the constant _UNICODE and follow the steps described in the online documentation, all your character variables and constant strings will be wide and the compiler will generate calls to the wide-character versions of the Win32 functions. This assumes that you use certain macros when you declare character pointers and arrays for example, TCHAR and _T. You'll hit a snag, though, if you try to run your MFC Unicode applications under Windows 95 or Windows 98, because they don't support Unicode internally. Even though Windows 95 and Windows 98 have wide-character versions of Win32 functions, those functions return a failure code. Windows NT, on the other hand, uses Unicode internally and has two versions of the Win32 functions that deal with characters. If you call a single-byte version, Windows NT makes the necessary conversions to and from wide characters. None of the sample programs in this book are configured for Unicode. All the programs use single-byte types such as char and single-byte string constants, and they do not define _UNICODE. If you run the samples under Windows NT, the operating system will do the necessary single-to-wide conversions; if you run them under Windows 95 or Windows 98, the interface is pure single-byte. One area in which you're forced to deal with wide characters is COM. All non-mfc COM functions (except DAO functions) that have string and character parameters require wide (OLECHAR) characters. If you write a non-unicode program, you must do the conversions yourself with the help of the MFC CString class and various MFC macros. If you want to write Unicode applications, read the Unicode chapter in Jeffrey Richter's Advanced Windows. You should also read the Unicode material in the Visual C++ online documentation.

11 Technical Notes and Sample Programs Technical Notes and Sample Programs The MSDN Library for Visual Studio 6.0 contains technical notes and sample programs that are referenced in this book. The technical notes, identified by number, are available from the Contents tab under the heading: MSDN Library Visual Studio 6.0 Visual C++ Documentation Reference Microsoft Foundation Class Library and Templates Microsoft Foundation Class Library MFC Technical Notes The MSDN CD-ROM also contains a number of MFC sample programs also referenced in the book and identified by name. These sample programs are documented under the heading: MSDN Library Visual Studio 6.0 Visual C++ Documentation Samples MFC Samples

12 Support Support Every effort has been made to ensure the accuracy of this book and the contents of the companion disc. Microsoft Press provides corrections for books through the Web at: If you have comments, questions, or ideas regarding this book or the companion disc, please send them to Microsoft Press using postal mail or Microsoft Press Attn: Programming Microsoft Visual C++ Editor One Microsoft Way Redmond, WA Please note that product support is not offered through the above mail addresses. For support information regarding Microsoft Visual C++, you can call the technical support line at (425) weekdays between 6 a.m. and 6 p.m. Pacific time. Microsoft also provides information about Visual C++ at and about the Microsoft Developer Network at