Statelessness làm cho Internet nhanh hơn, nhưng nhược điểm là HTTP của chính nó không thể phân biệt giữa người sử dụng khác nhau. Một máy chủ Web dựa trên tinh khiết HTML sẽ xử lý tất cả các yêu cầu với tình trạng tương tự, mà của một người sử dụng không rõ. Rõ ràng, nhu cầu hiện đại của Internet yêu cầu | Objects .NET Objects So far this chapter has looked at creating classes and objects. Earlier we talked about everything in .NET being an object. This is a core point to remember because it will aid you considerably in understanding .NET. Let s look at a couple of topics to understand how objects are organized and used within .NET. Namespaces Namespaces provide a logical separation for classes. The first step towards understanding objects in .NET is to understand namespaces. If you look at the number of classes that come as a part of .NET you ll see why - there are more than 3000 classes Having that number of classes without any form of structure would be really difficult to manage especially when searching through documentation. There are a couple of places you can look at the available namespaces. The first is the documentation that comes with .NET as shown in Figure 7-8 Figure 7-8 Observe the number of namespaces and how they have been broken down. Knowing the classes that belong in which namespace is essential not only to help you look up documentation but also to know about the namespaces to import into an page. The Class Browser Another useful tool is the class browser application which is available if you have installed and configured the .NET Framework SDK samples. To access this navigate to http localhost quickstart aspplus and scroll to the bottom where you ll see a link to Sample Applications and A Class Browser Application. Running this sample shows Figure 7-9 243 Chapter 7 Figure 7-9 On the left you see the namespace selecting one of these will display the classes in the namespace on the right side of the screen. Selecting an individual class will show its members. See Figure 7-10 Figure 7-10 .
