Introduce a book of a cool COM

Introduce a book of books of COM VCMFC Subscription 2000/02/28 Not allowed to reprint or copy this article without any institution or individual

The most effective way to get knowledge is to read, of course, read the book. It is no wonder that the ancients will be called "Reading". Introduction In fact, writing some articles introducing computer books is my long-lasting wish. On the one hand, since my friends often make me recommend some practical use of practical books, on the other hand, I am not very smooth in my earlier, I don't know if I have mixed "bustling" in the bookstore. . As a result, the heart is coming, as long as I feel almost, I bought it! As a result, I bought a lot of books that I didn't have to buy, and wasting money and wasted time. The year is, and there is some opinion on the computer book market, and some feelings have been produced. Most people are not sages, so they often have praise, but it is difficult to accept criticism. Many of my friends worry about my safety and advise me to say more. But the book is very inferior, and if there is a falsehood, it is inevitable that the truth is inevitable. So we met a "security policy": "Yang Shan" is dominated, after detailing a good book, it will make a few shortcomings, I will accept the author and the publishing house will still accept it. As for some irresponsible publications, I only say phenomenon, don't mention the name. (Please understand, floating in the world, safety first, safety first.) At present, the IT industry is competitive, the market is transformed. In order to survive, all people are overloaded by all aspects. When the programmer or manager is very difficult to explore the head from a large pile into a big creation, pick up a long-awaited professional book to enrich his own, they will certainly hope to convert the things in the book as soon as possible. Thoughts, so that this precious and brief buffer period learned more. But unfortunately, some books are not written for this purpose, and the words are as difficult as the text of the text (maybe some authors feel that only this can only show his horizontal unspeakable, maybe some author will not understand what it is. The content, I have to "shame" with a large pile of clouds. Not only that, but also more terrible phenomena, when computer books begin to show a strong sales momentum, countless "experts", "master" is emerging overnight, all kinds of name "Atmosphere" books, The training makes people look at it, just as many taxis on the street. And don't say what they have, I think, "more" seems to be a much truth that has been verified. I saw the publicity of "Intermet Training" in a badge bar of Beijing University, and it is really a crying. Nowadays, the shape-colored computer training class has become "a large landscape of IT culture." For this phenomenon, foreigners' comments seem to be more surprising: "In the United States, there is not so much training course, but a primary school students can operate computer." "In China, computer training class is everywhere, but computer The popularity of technology is still a problem. "" China's bicycle, men and women will ride, but have you seen a bicycle training class? If there is a bicycle training class, you are not tired of teach you the wheel diameter of your 'bicycle How long does it, how many spokes, etc., then believe that people who can ride bicycles will be less and less. "Writing book or translation, whether the unprecedented prosperity of computer books indicates that our level is very high? I think it is. Sometimes, in order to solve individual problems to find information, the result is often a waste of time, and I am still losing the feelings of "a big copy of the world". The ancestors of theme and form are very profitable, and I call it "popcorn phenomenon." The allusion is like this: the previous year, the street in front of my family has a popcorn because of the unique family, so the business is booming. But how long, after the rain, the spring bamboo shoots have emerged, and the word along the street is spectacular. Now everyone's business is not very good, but no one has no opinion, but my family is "rice flower fragrance".

If the spleen of the Chinese "follow the wind" is the ancestor pass, if the old people put it, if the authors should have some pioneers, calm down, think about it, what is the lack of books? Don't be "human cloud is also cloud". Although it is good to be a teacher, it is not so good, because you have to have a deep understanding of the knowledge telling, and you can use deep-in-depth language to listen to others. The attitude is of course the first, but the sacredness of the book is trampled by many author and publishing house. Some publishing houses regardless of quality, a festival is fast, and the business opportunities have, but fell the brand. A very good English book was translated by them, they didn't look at the horse, they could not see. Since the copyright is sold to them, other publishing agencies have a heartbeat that is powerful. A good book or even a good book is ruined, and the interests of interest is of course readers. In addition to the attitude, there is also a level, the book is not a person can write it. The names of many books in the times are more scary and scary, always reminds me of the street selling Dachi Pills: "As long as I eat my medicine, I can't get into the knife, and I will not be invaded." But in fact, many authors themselves have weak skills, can't write architecture and spirit, so I have a thousand articles that will be teaching everyone to press menu, select command, and the dialog box, press 'OK' ... ". The real teacher is not easy to find However, "Two Knife" is everywhere (just like a singe star with TV channels now, the movie star is dazzling). Plus some publishing houses are not strict, this is caused by personal You can go public, today, I introduce you to the book of COM, I hope to help the power of the COM. I want to learn COM must read books --- "COM technology inside" Title: "COM Technology insider "English name:" Inside COM "author :( US) Dale Rogerson Microsoft Press 1997 Chinese translator: Xiu Zhang Qinghua University Press, March 1999 first Edition price: 50.00 yuan (with CD)

Microsoft Press's "Inside ..." (translated into Chinese is "... technology insider") series books seem to have always maintained unique authority, rarely disappointment. From "Inside Ole" to "Inside Visual C ", it is very popular with readers. "Inside Visual C " said that the extensive extensive model, the language of the master, and the clear ideas make people not yet. However, it may be due to the reason, many people who want to learn Visual C face this thick masterpiece, I am always a little timid, worried that I don't understand myself. Shao Yong believes that as long as you have some basic knowledge of C (with Win32's concept more better), it is not difficult to learn this book, and of course, perseverance is a secret recipe against difficulties. "Inside COM" is also called a rare opportunity. The biggest feature of this book is that the language is relaxed, step-by-step, and it is not difficult to see that the author is really painful. In order to set the "threshold", the author has avoided a lot of difficulties and details of the facts such as type factories, registry in the first few chapters. I don't know if Dale Rogerson is not known as the "advantageous force". " The Enlightenment from the Command of Peng Command in the Korean War. In the arrangement of the sample program, each chapter has one to two procedures independent of other chapters, and the author as much as possible for these programs to be short and complete. On the one hand, it is relatively easy. On the other hand, the reader can put the focus of learning in the demand for COM components, without having to figure out those unnecessary details and complex practical problems in complex examples. In the programming language, the author uses the traditional C language, and does not involve any Win32 and MFC knowledge. In addition to some convenient interface pointers in Chapter 9, there is no template in other parts of the book. class. In short, the author will throw all the cums to make the reader to light up, as long as you have learned the standard C , there is an object-oriented programming basic concept (package, inheritance, polymorphism), you can read this Book. The first five chapters of the book are very clear, all of which are basic concepts such as components, interfaces, reference counts, interface queries, and DLL, without having to be less courageous. Slightly a bit of a little inadequacy is the following command: "cl client1.cpp ".cpp urid.lib" "cl / ld cmpnt1.cpp guids.cpp uuid.lib compnt1.def" and "nmake -F makefile. The problem is, how many people can be very skilled in writing a Makefile file and use the nmake and cl commands? I am afraid I have little. So the reader has to spend a lot of time to ponder the compilation process of the program, take time, pay, do not play food! Of course, as a scope of principles, these things should still be, but at least should tell the reader how to operate. I took the example of Chapter 5. The first is to establish a component DLL: Because of the VC , we don't have to use "CL / LD" to do it, just need to edit Cmpnt1.cpp, cmpnt1.def and ifce.h After guids.cpp, select an empty Win32 DLL project in the VC integrated environment, add these four files to the project, and CMPNT1.DLL is generated after compiling. Then to build a customer program: Many people often do this: first establish an empty Win32 project file, then add the edited standard C file to the project, but it is not connected.

Someone asked me more than once: How to establish a standard C project under VC ? (1), just write a standard C program, the more simple and better, such as: main () {return 1;} Save this file into your desire to build the same name as you want to build. (If you want the work name is apple, then you should save this file as apple.cpp). (2) Compile Apple.cpp, at this time, VC will prompt you not to build a project, whether he needs him to build one for you, of course, "Yes". So VC created an engineering of an Apple in a directory with apple.cpp. (3), the next is "crossing the river and bridge", remove apple.cpp from the project, join or edit the file you want. The first six chapters of the book are very clear, all of which are all basic concepts such as components, interfaces, reference counts, interface queries, and DLL, HRESULT, GUID, registry, etc., which are generally available, and there is no need to be less courageous. Chapter VII Test the Class Factory, use the class factory to create a component, may make people confuse: do not need a class, you can write the same powerful components, why do you want more? Shao Yong believes that if you only want to write components within a process, then this sentence is right, because you can write a full-time function to create all the components, then we can't see what is existing Necessity. However, if you want to create a component across the process, the situation is different: Can you write a "global function" that creates components in other processes and returns your handle? So Microsoft came up with a special component, with this special component to create other components, this special component is a class factory. During the creation of the processes, Class Factory Interface IclassFactory is the first across process. Chapter VII is a crucial chapter tells the reuse of components: inclusion and aggregation. Discussion on "COM is not object-oriented" seems to have been in progress. COM was accused of being a very poor technology because COM does not support the "inheritance" in traditional sense. Here we have to see this problem: Components have "independently released features" and "binary features", since it can be released independently, it should not depend on a base class, otherwise if the base class has changed, then the component has to follow Doing change, you can discuss independently. Component reuse is another realistic problem because some of the new components can save a lot of time with ready-to-build components, and COM uses inclusion and aggregation to achieve multiplexing of components, which is maintained for components. Independent publishing characteristics "," inheritance "is achieved. Hey! Call the "cat" "Mi". Le Shao Yong believes that about less and better, the better, measuring a technical quality standard is to see it is really easy to use, can solve our problem. About the sample program of this chapter is a little description: Careful readers may ask such a question: There is such a problem in the CMPNT1.CPP CA :: init () function: hr = m_punkn'anner-> queryinterface (IID_IY, (void **) & m_piy); In this sentence, the external component CA will get a pointer to the internal component IY interface. But the problem is generated, is it necessary to call NondelegatingQueryInterface? It should be that there is a seemingly used, because we have to get a pointer to non-proxy unknown interface.

What is the case? The agent unknown interface further forwards the request to the external component, and the external component is pushed back to the internal components to form a dead cycle. But running an example program, I found that the dead cycle did not appear, everything is normal! why? A closer look suddenly wake up: Pursue the origin of the M_PunkNownNiner pointer, found that it is a non-agent unknown interface to the internal components, that is to say that the call is actually NondelegatingQueryInterface, of course, will not be wrong (this is also object-oriented polymorphism) An embodying). Chapter 9 In addition to the intelligent pointer, there is basically no new concept (actually intelligent pointer is not new, Visual C supports intelligent pointers). As for CunkNown and CFactory, as long as you understand the first eight chapters, understand what they are not difficult. As for the next three chapters ... ... It is said that this book is coming, from the views of the reader feedback, it is quite a lot of criticism. Shao Yong's view is as follows: First, the results are main, because COM's cross-trip call is indeed complicated, Shao Yong also spent the nine bull two tiger's strengths "Dial the cloud, see the day", can speak this look is not easy. But readers have opinions on books. It is mainly because they don't understand, they hope to speak a complex knowledge with the most popular language, and strict. Therefore, the statement and concept of these chapters need to be a lot, and it should be strengthened for DCOM (but this does have a certain difficulty). The final book provides an example of a jigsaw puzzle. Interested readers can study, play, hard work for a long time, and it should be relaxed. Writing in the end of the book: "After understanding all the content introduced by this book, the reader should be able to be a COM expert." But Shao Yong thought that this is always too early. If you make COM's knowledge than a "big tree model", then this book only solves the most basic problem, that is, the first tree of the big tree. The main part of the body. If you completely understand COM, you should also understand each of the branches of this big tree, each leaves and worms on the leaves. The book worth a visit --- "COM / DCOM Programming Guide" Title: "COM / DCOM Programming Guide" English name: "COM / DCOM Primer Plus" author :( US) Corry, Mayfield, Cadman Sams Publishing 1999 Chinese translation : Liu Yuncheng, Lei Qinghua University Press, January 2000, 1st, Price: 52.00 yuan (with CD)

The SAMS published by the book occupied the market with its unique perspective, and the readers were quite good. Look at their books may be a shortcut to a quick entry. When the COM book is very short, the "COM / DCOM Programming Guide" is called a book worth seeing. Shao Yong's evaluation of this book is: About the principle discussion in the rules, there is no obvious flaw, and the language is quite wide, the language is still full, but it is also very rare, but it is unfortunate enough, not deep enough, so It is not a "COM monograph". After reading this book, you will close our eyes, just if you have a big meal after you eat a big meal, there is no dish is the "big kitchen craft", which is inevitable. However, from a practical point of view, this book is also called the superiority, and it is not preferentially given a complete example. In Chapter 10, the configuration example of DCOMCNFG is also given. It is rare. If the reader looks at this book and other books, the "Guide" is a good "Two Leaders" (seeing the translator, I really spend a thought, falling) Also very decent). The consistent style of SAMS's book is the threshold, and there is basically no pain in learning. However, COM is a relatively advanced technology, and "zero pain" learning seems unlikely, and SAMS always strives to be practical, so it is unable to mention some practical examples, so the knowledge involved is much more. If you are not understanding C , event driver programming, and MFC, you should see some books of relevant knowledge before reading this book. The discussion of the Interface Definition Language (IDL) can be regarded as a flash point. IDL is originally not designed to describe a method of describing COM classes and interfaces, but an open software foundation for the RPC IDL specified by the Distributed Computing Environment (DCE). Microsoft initially envisaged the IDL to describe a method of using the RPC interface that can be used between Windows NT machines, which later gradually adds a number of keywords dedicated to the COM component to describe the COM interface and COM objects. Talking about IDL and ODL, there may be a lot of readers feel confused. However, there is no way, this is a historical legacy issue, and the discussion on page 170 is believed to give you a satisfactory answer. Americans write books, I like to write some background culture, Shao Yong is very appreciated. For example, in this book, "COM's lifestyle", it is realistic, and the spirit is one of them. DON BOX is a character of a COM field. It often meets his masterpiece in MSDN. The "COM lifestyle" is actually different from COM programming and traditional C program development and in software Engineering changes. The book is as follows: "I strongly recommend that you start all programming with IDL, don't use IDL just to generate a proxy and placeholder module of the local server. It is like Don Box once said, 'Real COM programmer IDL starts working '". Although Shao Yong is very respectful to the master, it is still considered that this is too absolute and extreme. Because Don Box is actually an ideal software development method, we can't encounter. According to DON BOX theory, if we develop a project, all of which use COM components, then you should design all interfaces before starting programming, because the interface is invariant, it should not change, so it should be from IDL Start all the work. Back in reality, our programmers are in the same product, generally construct a program framework, and the component is just some basic functions, not all of the project, and the master's remark is not suitable for us. Many people think that "in software, the United States is our tomorrow", so they have used Americans to read them as Bible.

But Shao Yong said: "At the same time, there must be a choice. Think, see it is not in line with China's national conditions." The last chapter of the book uses the previously described content to create an example of a real distributed application, suggestion The reader carefully studied (including other procedures in this book), be brave enough to eat crabs. Otherwise, even if you have a little bit of oil, tell you how delicious crabs, there may be no more people. Highly recommended! COM's "jewel monograph" --- "COM" Principles and Applications Title: "COM Principles and Applications" Author: Pan Aimin Tsinghua University Press, November 1999 first edition Price: 39.00 yuan

The simple appearance of the simple appearance, a strange name, the price of almost white delivery is the first feeling of Shao Yong's first book. But opened this book, after browsing, Le Shao Yong suddenly "Heartbeat accelerated, headed up", smashed his eyes, there is a joy of gold. So one chapter, one chapter, the more you look at it, the more you read more, you can't help but exclaim: "This book is a collection of COM!"! Le Shao Yong believes that this book has four characteristics of "systemic, rigorous, in-depth, practicality". "Systemic" is to say that the knowledge discussed in this book involves all aspects of the COM area, not only comprehensive, and the system. Looking at the end of Pan Aimin's skills, he can do it, but he will not only study COM, but also to C 's understanding is also a fire pure (the author translated "Visual C technology insider" [fourth edition] Therefore, therefore, it is clear, and there is a confirmed system. It is like the water of the Yangtze River, which makes people feel refreshed and linger. "Strictness" is that the phrase wording in the book is quite paying attention to the scrutiny. In some places, it seems that there is a suspect, but the product is carefully discovered, but she has not understood so deeply before. "In-depth" is that this book is not a general book, and many of the discussing discussions are superb, giving people a new feeling, which is a masterpiece. Since the author's skill is deep, the combination of theory and practice can be described as "seamless", so "practicality" is also a major characteristic of this book. The book is divided into three parts, and the first part includes the top five chapters, telling the principle of COM. Le Shao Yong believes that if several show is the same topic, it is easy to see the level of the level. Regarding the most basic concepts such as components, interfaces, DLLs, and cross-trip calls may be speaking on COM books, but they are different. In this book, the author not only tells the basic theory, but also has a collection, processing, and many places have made a summary, and it is very organized to say "one, two, three" to the reader. With many people now take the English information to fight together, you can "pile" and a book, the author's practice is really difficult. The fourth chapter tells the transparency of the client program to create a COM object. Everyone knows that whether it is the process within the process or the processes, the client can create a COM object with a consistent way. For components within the process, whether it is creation process, or the calling process of the interface function, we can understand the interaction between components and customers in accordance with the general same process internal function calls; but for process external components, actual situation Most of the complicated, because component programs and client have different process space, so all interactions between them involve communication between processes. Although client programs and objects are in different process spaces, all the calls of the interface are indirect, the client call interface member function is the same as the function in this process, which is the transparent effect of COM. In this section, the author not only introduces the memory model of the component process and the customer process, but also discusses a detailed discussion on the column call process in the interface call, and gives a standard column for customizing the interface. The process of the assembly program will be described in example with example explanation of the implementation process of the process external component custom interface. Shao Yong believes that this part of the discussion is not in-depth, and it is very standard. Taking the column of the class object as an example, there is a discussion in the book: "(1), first determine the CLSID of the agent object provided by the registration object (ie the class object), if the registration object cannot provide the CLSID of the agent object, then Use standard column set proxy objects.

Then the CoregisterClassObject function requires the registration object to provide a column set packet, which is actually a byte stream that contains information necessary for a proxy object to connect the cross-trip connection of the component object. If the registration object cannot provide such a packet, use the standard column packet provided by COM. (2), COM transmits the CLSID and column packets of the agent object to the customer process, and the CogetherClassObject function is waiting for this data. (3) In the customer process, COM creates a proxy object based on the transferred CLSID and passes the column packet to the agent object. Because the column set packet contains the connection information of the proxy object and component object, the proxy object uses the packet to establish a connection to the component. "The discussion of this summary is almost all the chapters of the book. It can be made to this book is very rare, but the author does not have a pen, he also introduces the iMarshal interface, and gives a custom column Implementation. As such knowledge, you may not find it in other books. Chapter 5, "Developing COM Apps with Visual C " mainly discussed from two aspects, one is MFC, one is ATL. Due to the author In Visual C , this part can be first none in the same kind of book in this section. I said that when the general book is talking about it, the mechanism to implement the COM interface with MFC is often Revenue, but most of the discussion is not enough, Shao Yong has a feeling of "walking out of the restaurant but there is nothing to eat", but this book is done, through the DECLAARE_ITERFACE_MAP (), Begin_Interface_map, end_interface_map, interface_part, Init_INTERFACE_PART, etc., the reader can make readers how to implement the COM interface, how to define interface mapping tables has a comprehensive understanding. If you need to write COM components with MFC, I believe it will be unrestricted from benefit. Next for ATL's discussion is slightly thin, but the content is essential, with a high reference value. Leisurely believe that today's increasing importance today, the market is still lacking a system to tell ATL books, but I don't know which one "Heroes" has a mood to fill this lack. The second part of the book is six to ten chapters, telling some of the contents of the expansion in the COM specification, including connectivity object communication mechanism, structure storage technology, and COM object's name object technology, Unified transmission mechanism and DCOM. If the reader has to fully understand COM, this part of the content provides you with the details of these technologies. Previously, there were few books to introduce these technologies, even if there are occasional books involving one or two, nor Very deep. And this part of the knowledge involves many practical problems in COM applications. For example, OLE, although it has been born for many years, most people are still a semi-solving, master is very insufficient. Although you can do it from a variety of media you can Find a lot of information, but put these information out of systematically, it is not very common. Throughout these chapters, it can be seen that the author must seriously study the COM architecture and OLE's internal information and source code, and pass own The machining made these originally broken and unnecessary materials made a "delicious meal". "It's rare, rare," Shao Yong read these chapters, could not help but praise, "Collectors also! (In fact, every topic here is a lot of feelings to share with you, but unfortunately, you can only introduce the most exciting parts, want to know more, or buy a slow home. Slowly see.) DCOM has to say, it is the inevitable thing for COM from the desktop environment to the distributed network environment.

From COM, it has gradually reached DCOM. This part is a model of "in-depth light", not only detail the principles and characteristics of DCOM, but how users create DCOM components, but also discussion on connection management, concurrency management. Remember that I spent the last few chapters when I commented on the "COM technology insider"? So, the books of Mr. Pan Aimin make up for your shortcomings. In the second part, my last topic is about security, because it is too important for a distributed system. "COM principle and application" discusses security in two places, the first time in Chapter 4, it is mentioned that activation security and call security. Here, COM security is described here from the perspective of COM characteristics, focusing on the security model structure. The second time is in Chapter 10, mentioned access security and excitation security, focusing on the configuration of the security model in the distributed environment, emphasizes practicality. At this point, some readers may feel that these four "security" mix together, bumps, stir mix, but it is a good dish, but unfortunately don't understand. Le Shao Yong believes that this is just because there are too many nouns in the COM, and it is very confusing, and Microsoft is not yet. Therefore, this is really difficult for those who write books. So some authors have adopted a policies that activate security and call security, without accessing security and stimulating security, and if access security and excitation security are only word for security and call security. Not mentioned. Think although it is difficult to solve it, it is not conducive to readers to build a complete concept. "COM principle and application" did not avoid difficulties, and its "in-depth" has also been reflected again. It can be seen, when writing this part, the author also got a job, he made a level of COM safety with a different point of view, I think it is valuable to have two: one, The information of COM is very difficult. About the safety materials are less, it is not easy to collect the information of the comparative system; second, there is basically no authoritative discussion before this part of the knowledge, the people who write books Enconscent, this requires the author to have a good skill and understand, of course, has also had a hard effort. To be honest, this part of the book is less than a few times, and there is a lot of knowledge. My suggestion is that when reading this section, I remember to be meticulous but don't drill the horns, otherwise it may really come around for a while. Also, because the security of DCOM is based on NT security, many places involve the security policy of distributed systems, so you'd better have the basics of this aspect, if not, don't understand is normal Do things. Through the study of the top two parts of this book, you have a relatively comprehensive understanding of the basic principles and extensions of COM, just like covering a house, you have already made a solid foundation and start the wall, it is really a welcome A congratulations! But this is not enough, because we learn how to use it well. Therefore, the third part must be conducted, where you will learn from both COM advantages and practical technology, the author will teach you how to cover the roof of the house. The eleventh chapter of the book tells the automation object. The concept of automation appears in OLE2 at the time, called OLE Automation. Later, this concept was absorbed by COM, called automation. Automated concepts are introduced in a wide variety of Control, Word and Execl also support automation. This is often the case, the more it is, the brighter, the brighter it is, the next one is just right. Automation is, this is, and various data is always can't catch the focus. "Inside COM" discussion about automation is also very satisfactory, and "COM principle and application" is compensated for this shortage.

We know that COM substantially defines a communication method for customers and servers, and this communication is done through an interface. When we use C to write a client program, everything is so beautiful, and a interface pointer will be obtained through CocreateInstance and QueryInterface, and the corresponding function can be called through this interface pointer. Please note that all this is made through a pointer. But when we write a customer program with Visual Basic, the situation is not so beautiful, only one: Visual Basic is a weak type programming language, which is very limited in the data type. Therefore, we must propose a scheme that allows interpretative languages ​​to access components, this program is called automation. An automation server is actually a COM component that implements the IDispatch interface, and an automation controller is a COM customer that communicates with the IdisPatch interface with the automation server. In this chapter, the author has a detailed discussion and a good example of the programming of the IDSPATCH interface and related data type, the implementation, dual interface, and late binding and early binding, and the programming of the automation objects. Another flash point. Chapter 12 tells ActiveX control. In this chapter, the author not only detailed the basic theory of ActiveX control, but also discussed in depth on how to apply ActiveX control in the Internet environment. Therefore, this chapter is an unsatisfactory information that has some readers with some basic knowledge of this area. Since the authors have made some extravagance in order to save space, some places may have certain jumping sense, but there are many ways to introduce the ActiveX foundation. Since the author is very familiar with MFC, the example of this chapter still uses MFC to prepare and conducts in-depth analysis, which is a good opportunity for C enthusiasts. As a software model, CoM not only provides standards between procedures and procedures, but also changing traditional programming methods. Therefore, the main contribution of COM is to change the programming method. Chapter 13 of the book tells the COM-based programming. In this chapter, the author has analyzed the object-oriented programming method and compared with the component chemical design, and discusses MTS, and The layer application software structure and COM-based web application have been introduced to enable readers to create a comprehensive understanding of the component. Although MTS has been introduced for a while, there are not many people who are truly used. Many explorations only stay in theory, which makes the advantages of MTS have not been known by the vast number of Windows programmers. However, with the release of Windows2000 and the release of COM , this situation will change soon. COM is integrated with COM, DCOM, MTS, which enhances component software to the application layer through various support of the operating system, and all underlying details are left to the operating system. The last chapter of the book introduces COM , which is very important in understanding the services provided by Windows2000. "COM principle and application" is the power of Mr. Pan Aimin, I think it is two: one, this book is very good at the consistency and noun before and after, readers get "authentic" COM Chinese books It is significantly different from the translation work. Second, the domestic writer can write such a works such as (or even the writer of the United States). For us, it is indeed a rejoicant thing, but it will be in the near future, such books will be increasingly more.