Starting from a small example, we often need to see some multimedia information when online browsing the web, such as one end small video, isn't the browser including IE, add a multimedia playback function? The answer is obviously negative. But obviously we have also seen the content we needed. Everyone will definitely say, because our system has playing software like Media Player, Realone Player, the browser will automatically call it when you need it. OK, you have such a personal feeling, you will be very easy in the technology of learning COM.
But it has to be added to you about the knowledge about the server and the client because it is often involved in the later content. Just as the explanation of "culture", there is a narrow and generalized interpretation. The narrow people may be the scientific and cultural knowledge, cultural aquatic products, etc. of primary schools and even junior high schools. In short, it is a knowledge of a person. That's now, change an angle, say national culture, corporate culture, and even diet culture, etc., these are cultural. What about the server and the client? In front of us to learn the database, there is a SQL Server server. When learning the ASP, there is an IIS server, which can be called the narrow server we understand, and the browser is the client, the browser, the browser, the browser Those, we can say that programs that call or use other programs, components, and even more tiny program are the client, and the party that is dropped is the server. The definition of the server and the client is not absolute, and the location between them can be fully transformed in different function call relationships.
?
So what is CoM? We may wish to analyze from above. First, one application (IE) that is being used (IE) requires a certain function (above is playing video), but it does not have, then we solve the problem method is obviously from new development. Version makes it a function of this, which is obviously not a happy thing to our programmer, is there any other way? By the way, as I saw in the example above, it can use other applications that implement this feature (MEDIA Player, Realone Player), which is based on the explanation of the previous paragraph, IE should be the client, The multimedia player should be a server. Now there is a new problem, how do I find Realone Player? Don't forget the core file of the Windows operating system System.dat (registry), each of our programs on Windows must be registered in the registry, and then various programs can be easily found according to the registry. Which one is needed.
OK, now we will come to COM, in the above example, we have encountered such a hassle, we hope to use the functions of using other applications using our application, but you don't know how to Do it, this kind of COM came out, it said to me: a young man, you should do this, find a place, specifically register your program, and your procedure must be a piece of interface, where you want to detail Describe their features, indicating their address, which can be very convenient to find them when needed. This is com, he tells me so much. So com is just a standard, it is an implementation of guidelines. He is a guiding ideology. It is a blue book, he is completely theoretical, not a realistic thing. What is the registry and those procedural? Yes, they are an implementation of COM technology, and the result we see is a manifestation of this implementation technology.
?
?
