In order to make users better enjoy the convenience of distributed procedures, in order to make programmers to write better distributed programs, Microsoft's comprehensive fat client and thin customers put forward the concept of intelligent clients, this The new technology will bring to the user a new experience, which can be said to be the advantage of combining the original client form, and avoiding the disadvantage, in the future, it should be able to pass on a big way. In order to achieve this form of intelligent client, Microsoft provides our programmer to help us, all Application Block is fully open, we can not only use them directly into the solution, but also All source code can be viewed and modified (although Microsoft does not advocate the modified source code, we can directly inherit the use for different places, after all, is it object-oriented program), even the structure of the structure, we can find it, This complete public will undoubtedly be great to us, not only allow us to taste the dessert multiplexed, and can learn from many excellent ideas. Now, according to things you have learned in the process of learning, and some of your experience in supporting the structure of Application Blocks supporting the intelligent client in programming, sharing, and make progress together with you. First we can see that Microsoft's multiple Application Blocks can complete a specific function, but it is not completely independent, with each other, which makes them can constitute smart customers. This system, can play a single application block or the function does not have to add, which should be a point of view of systemism. Secondly, in the process of the design and implementation of Application Blocks, a large number of design patterns, really should "there is no program that does not use the mode", this is also a big better understanding design pattern for us. . Because of this, the design pattern is a good thing, but it is really not easy to use it well. In the following we can see how it is designed in Application Blocks. Let's take a look at what Application Block uses what application blocks in the implementation of the intelligent client. Primary Application Block 1, Data Access Application Block: Responsible for data access, in which Microsoft attempts to implement distributed databases at least local map transparency, because it uses an interface to implement different databases Operation, that is, whether it is Oracle in the data layer, it is SQL Server or DB2, we do not need to make specific programming for each database, only need to pass this Application Block. Then the corresponding method and the format of the SQL statement are automatically complete by this block. This avoids writing different programs for different database types in a distributed program. 2, OFFLINE Application Block: The business responsible for handling the time when it is offline. Because in the use of smart clients, we cannot encounter offline status. This mode of operation is a disaster in B / S mode, because we cannot obtain relevant data from the server, and we cannot feed our operations to the server, so that our work cannot be done normally. And in this application block, we can achieve perfect offline functionality.
