毕业论文英文文献及翻译文档格式.docx

1、Finally, most programming languages have similar variable data types. In most languages, you have some means of representing strings and integers, for example. The maximum and minimum size of an integer might depend on the language, but the basic data type is the same. Maintaining all this functiona

2、lity for multiple languages requires a lot of work. Why keep reinventing the wheel? Wouldnt it be easier to create all this functionality once and use it for every language? The .NET Framework Class Library does exactly that. It consists of a vast set of classes designed to satisfy any conceivable p

3、rogramming need. For example, the .NET framework contains classes for handling database access, working with the file system, manipulating text, and generating graphics. In addition, it contains more specialized classes for performing tasks such as working with regular expressions and handling netwo

4、rk protocols. The .NET framework, furthermore, contains classes that represent all the basic variable data types such as strings, integers, bytes, characters, and arrays. Most importantly, for purposes of this book, the .NET Framework Class Library contains classes for building ASP.NET pages. You ne

5、ed to understand, however, that you can access any of the .NET framework classes when you are building your ASP.NET pages. Understanding NamespacesAs you might guess, the .NET framework is huge. It contains thousands of classes （over 3,400）. Fortunately, the classes are not simply jumbled together.

6、The classes of the .NET framework are organized into a hierarchy of namespaces. ASP Classic Note In previous versions of Active Server Pages, you had access to only five standard classes （the Response, Request, Session, Application, and Server objects）. ASP.NET, in contrast, provides you with access

7、 to over 3,400 classes!A namespace is a logical grouping of classes. For example, all the classes that relate to working with the file system are gathered together into the System.IO namespace. The namespaces are organized into a hierarchy （a logical tree）. At the root of the tree is the System name

8、space. This namespace contains all the classes for the base data types, such as strings and arrays. It also contains classes for working with random numbers and dates and times. You can uniquely identify any class in the .NET framework by using the full namespace of the class. For example, to unique

9、ly refer to the class that represents a file system file （the File class）, you would use the following:System.IO.File System.IO refers to the namespace, and File refers to the particular class. NOTE You can view all the namespaces of the standard classes in the .NET Framework Class Library by viewin

10、g the Reference Documentation for the .NET Framework.Standard ASP.NET NamespacesThe classes contained in a select number of namespaces are available in your ASP.NET pages by default. （You must explicitly import other namespaces.） These default namespaces contain classes that you use most often in yo

11、ur ASP.NET applications:System Contains all the base data types and other useful classes such as those related to generating random numbers and working with dates and times. System.Collections Contains classes for working with standard collection types such as hash tables, and array lists. System.Co

12、llections.Specialized Contains classes that represent specialized collections such as linked lists and string collections. System.Configuration Contains classes for working with configuration files （Web.config files）. System.Text Contains classes for encoding, decoding, and manipulating the contents

13、 of strings. System.Text.RegularExpressions Contains classes for performing regular expression match and replace operations. System.Web Contains the basic classes for working with the World Wide Web, including classes for representing browser requests and server responses. System.Web.Caching Contain

14、s classes used for caching the content of pages and classes for performing custom caching operations. System.Web.Security Contains classes for implementing authentication and authorization such as Forms and Passport authentication. System.Web.SessionState Contains classes for implementing session st

15、ate. System.Web.UI Contains the basic classes used in building the user interface of ASP.NET pages. System.Web.UI.HTMLControls Contains the classes for the HTML controls. System.Web.UI.WebControls Contains the classes for the Web controls.NET Framework-Compatible LanguagesFor purposes of this book,

16、you will write the application logic for your ASP.NET pages using Visual Basic as your programming language. It is the default language for ASP.NET pages （and the most popular programming language in the world）. Although you stick to Visual Basic in this book, you also need to understand that you ca

17、n create ASP.NET pages by using any language that supports the .NET Common Language Runtime. Out of the box, this includes C# （pronounced See Sharp）, JScript.NET （the .NET version of JavaScript）, and the Managed Extensions to C+.NOTEThe CD included with this book contains C# versions of all the code

18、 samples.Dozens of other languages created by companies other than Microsoft have been developed to work with the .NET framework. Some examples of these other languages include Python, SmallTalk, Eiffel, and COBOL. This means that you could, if you really wanted to, write ASP.NET pages using COBOL.R

19、egardless of the language that you use to develop your ASP.NET pages, you need to understand that ASP.NET pages are compiled before they are executed. This means that ASP.NET pages can execute very quickly.The first time you request an ASP.NET page, the page is compiled into a .NET class, and the re

20、sulting class file is saved beneath a special directory on your server named Temporary ASP.NET Files. For each and every ASP.NET page, a corresponding class file appears in the Temporary ASP.NET Files directory. Whenever you request the same ASP.NET page in the future, the corresponding class file i

21、s executed.When an ASP.NET page is compiled, it is not compiled directly into machine code. Instead, it is compiled into an intermediate-level language called Microsoft Intermediate Language （MSIL）. All .NET-compatible languages are compiled into this intermediate language. An ASP.NET page isnt comp

22、iled into native machine code until it is actually requested by a browser. At that point, the class file contained in the Temporary ASP.NET Files directory is compiled with the .NET framework Just in Time （JIT） compiler and executed. The magical aspect of this whole process is that it happens automa

23、tically in the background. All you have to do is create a text file with the source code for your ASP.NET page, and the .NET framework handles all the hard work of converting it into compiled code for you. ASP CLASSIC NOTE What about VBScript? Before ASP.NET, VBScript was the most popular language f

24、or developing Active Server Pages. ASP.NET does not support VBScript, and this is good news. Visual Basic is a superset of VBScript, which means that Visual Basic has all the functionality of VBScript and more. So, you have a richer set of functions and statements with Visual Basic. Furthermore, unl

25、ike VBScript, Visual Basic is a compiled language. This means that if you use Visual Basic to rewrite the same code that you wrote with VBScript, you can get better performance. If you have worked only with VBScript and not Visual Basic in the past, dont worry. Since VBScript is so closely related t

26、o Visual Basic, youll find it easy to make the transition between the two languages.NOTE Microsoft includes an interesting tool named the IL Disassembler （ILDASM） with the .NET framework. You can use this tool to view the disassembled code for any of the ASP.NET classes in the Temporary ASP.NET File

27、s directory. It lists all the methods and properties of the class and enables you to view the intermediate-level code. This tool also works with all the ASP.NET controls discussed in this chapter. For example, you can use the IL Disassembler to view the intermediate-level code for the TextBox contro

28、l （located in a file named System.Web.dll）.中文翻译ASP.NET 和 .NET FrameworkASP.NET是微软.NET框架总体战略的一部分。它包含了一组满足各种可以想象到的需求的类。在之后的两个部分，你将会学到ASP.NET是怎样融合到.NET框架中去的，而且你将会学到可以在ASP.NET页面中使用到的语言。.NET框架类库 假设你就是微软，假设你必须支持多语言编程，例如VB,JS,C+。这些语言的很多函数都重复了，比如对于每种语言，你都必须包含一些访问文件系统，与数据库打交道，以及处理字符串的函数。而且这些语言都包含了相似的变成结构。每种语

29、言都有循环和条件语句。虽然条件语句的语法有些出入，但是功能还是一样的。最后，很多变成语言都有相似的变量类型定义。在很多语言中，你都可以表达出字符串类型和整型。整型数的最大和最小值则由语言本身决定，但基本的表量类型还是相同的。维护所有这些语言的函数会很费事。干吗要不断的重复历史的车轮？如果只对函数建立一次而后对每种语言都使用是否会更爽些？而.net框架类库正是如此，它包含了一组为满足变成需要而设计的类。举例来说，.net框架包含了处理数据库访问的一组类。同时还有文件系统处理类以及视图产生类。而且，他包含了更多的较为细化的用来处理正则表达式和网络协议的类。更重要的是，.net框架还将所有一些基础变量都表示了出来，例如字符串类型，整型，字符型和数组。最重要的也是本书的主要目的，.net框架类库包含了用来建立页面的类。你需要明白的是，你可以在建立自己的页面的时候访问任