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1、 毕业设计外文资料翻译 题 目 ASP.NET 技术 学 院 XXXXXXXXXXXX 专 业 XXXXX 班 级 XXXX 学 生 XX 学 号 XXXXXXXXX 指导教师 XXX 二一 三 年 三 月 十 日 济南大学毕业设计外文资料翻译-2-Advanced ASP.NET AJAX Server Controls,2009,177(5):97-102.ASP.NET Technique Adam Calderon Joel Rumerman 1.Building ASP.NET Pages ASP.NET and the.NET Framework ASP.NET is part o
2、f Microsofts overall.NET framework,which contains a vast set of programming classes designed to satisfy any conceivable programming need.In the following two sections,you learn how ASP.NET fits within the.NET framework,and you learn about the languages you can use in your ASP.NET pages.The.NET Frame
3、work Class Library Imagine that you are Microsoft.Imagine that you have to support multiple programming languagessuch as Visual Basic,JScript,and C+.A great deal of the functionality of these programming languages overlaps.For example,for each language,you would have to include methods for accessing
4、 the file system,working with databases,and manipulating strings.Furthermore,these languages contain similar programming constructs.Every language,for example,can represent loops and conditionals.Even though the syntax of a conditional written in Visual Basic differs from the syntax of a conditional
5、 written in C+,the programming function is the same.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 ty
6、pe is the same.Maintaining all this functionality 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 class
7、es designed to satisfy any conceivable programming 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 regula
8、r expressions and handling network protocols.The.NET framework,furthermore,contains classes that represent all the basic variable data types such as strings,integers,bytes,characters,and arrays.济南大学毕业设计外文资料翻译-3-Most importantly,for purposes of this book,the.NET Framework Class Library contains class
9、es for building ASP.NET pages.You need to understand,however,that you can access any of the.NET framework classes when you are building your ASP.NET pages.Understanding Namespaces As you might guess,the.NET framework is huge.It contains thousands of classes(over 3,400).Fortunately,the classes are no
10、t simply jumbled together.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
11、you with access 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 S
12、ystem namespace.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 uni
13、quely 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 viewing
14、the Reference Documentation for the.NET Framework.Standard ASP.NET Namespaces The 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 your A
15、SP.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.济南大学毕业设计外文资料翻译-4
16、-System.Collections.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 con
17、tents 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 Contai
18、ns 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 sta
19、te.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 Languages For purposes of this book,you
20、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.Although you stick to Visual Basic in this book,you also need to understand that you can create ASP.NET pages by using any language that supports the.N
21、ET Common Language Runtime.Out of the box,this includes C#,JScript.NET,and the Managed Extensions to C+.NOTE The CD included with this book contains C#versions of all the code samples.Dozens of other languages created by companies other than Microsoft have been developed to work with the.NET framewo
22、rk.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.济南大学毕业设计外文资料翻译-5-Regardless of the language that you use to develop your ASP.NET pages,you need to understand that ASP.NET pages are c
23、ompiled 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 resulting class file is saved beneath a special directory on your server named Temporary ASP.NET Files.For each and every A
24、SP.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 is executed.When an ASP.NET page is compiled,it is not compiled directly into machine code.Instead,it is compiled into an inte
25、rmediate-level language called Microsoft Intermediate Language(MSIL).All.NET-compatible languages are compiled into this intermediate language.An ASP.NET page isnt compiled into native machine code until it is actually requested by a browser.At that point,the class file contained in the Temporary AS
26、P.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 automatically 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 handle
27、s 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 for developing Active Server Pages.ASP.NET does not support VBScript,and this is good news.Visual Basic is a superset of VBScript,which means tha
28、t Visual Basic has all the functionality of VBScript and more.So,you have a richer set of functions and statements with Visual Basic.Furthermore,unlike 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 g
29、et better performance.If you have worked only with VBScript and not Visual Basic in the past,dont worry.Since VBScript is so closely related to Visual Basic,youll find it easy to make the transition between the two languages.NOTE Microsoft includes an interesting tool named the IL Disassembler(ILDAS
30、M)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 Files directory.It lists all the methods and properties of the class and enables you to view the intermediate-level code.济南大学毕业设计外文资料翻译-6-This tool also works with all
31、 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 control(located in a file named System.Web.dll).Introducing ASP.NET Controls ASP.NET controls provide the dynamic and interactive portions of the user inter
32、face for your Web application.The controls render the content that the users of your Web site actually see and interact with.For example,you can use controls to create HTML form elements,interactive calendars,and rotating banner advertisements.ASP.NET controls coexist peacefully with HTML content.Ty
33、pically,you create the static areas of your Web pages with normal HTML content and create the dynamic or interactive portions with ASP.NET controls.The best way to understand how ASP.NET controls work in an HTML page is to look at a simple Web Forms Page.Adding Application Logic to an ASP.NET Page T
34、he second building block of an ASP.NET page is the application logic,which is the actual programming code in the page.You add application logic to a page to handle both control and page events.If a user clicks a Button control within an HTML form,for example,the Button control raises an event(the Cl
35、ick event).Typically,you want to add code to the page that does something in response to this event.For example,when someone clicks the Button control,you might want to save the form data to a file or database.Controls are not the only things that can raise events.An ASP.NET page itself raises sever
36、al events every time it is requested.For example,whenever you request a page,the pages Load event is triggered.You can add application logic to the page that executes whenever the Load event occurs.2.Building Forms with Web Server Controls Building Smart Forms You use several of the basic Web contro
37、ls to represent standard HTML form elements such as radio buttons,text boxes,and list boxes.You can use these controls in your ASP.NET pages to create the user interface for your Web application.The following sections provide detailed overviews and programming samples for each of these Web controls.
38、Controlling Page Navigation In the following sections,you learn how to control how a user moves from one ASP.NET page to another.First,you learn how to submit an HTML form to another page and retrieve form information.Next,you learn how to use the Redirect()method to automatically 济南大学毕业设计外文资料翻译-7-t
39、ransfer a user to a new page.Finally,you learn how to link pages together with the HyperLink control.Applying Formatting to Controls In the following sections,you learn how to make more attractive Web forms.First,you look at an overview of the formatting properties common to all Web controls;they ar
40、e the formatting properties of the base control class.Next,you learn how to apply Cascading Style Sheet styles and classes to Web controls.3.Performing Form Validation with Validation Controls Using Client-side Validation Traditionally,Web developers have faced a tough choice when adding form valida
41、tion logic to their pages.You can add form validation routines to your server-side code,or you can add the validation routines to your client-side code.The advantage of writing validation logic in client-side code is that you can provide instant feedback to your users.For example,if a user neglects
42、to enter a value in a required form field,you can instantly display an error message without requiring a roundtrip back to the server.People really like client-side validation.It looks great and creates a better overall user experience.The problem,however,is that it does not work with all browsers.N
43、ot all browsers support JavaScript,and different versions of browsers support different versions of JavaScript,so client-side validation is never guaranteed to work.For this reason,in the past,many developers decided to add all their form validation logic exclusively to server-side code.Because serv
44、er-side code functions correctly with any browser,this course of action was safer.Fortunately,the Validation controls discussed in this chapter do not force you to make this difficult choice.The Validation controls automatically generate both client-side and server-side code.If a browser is capable
45、of supporting JavaScript,client-side validation scripts are automatically sent to the browser.If a browser is incapable of supporting JavaScript,the validation routines are automatically implemented in server-side code.You should be warned,however,that client-side validation works only with Microsof
46、t Internet Explorer version 4.0 and higher.In particular,the client-side scripts discussed in this chapter do not work with any version of Netscape Navigator.Requiring Fields:The RequiredFieldValidator Control You use RequiredFieldValidator in a Web form to check whether a control has a value.Typica
47、lly,you use this control with a TextBox control.However,nothing is wrong with using RequiredFieldValidator with other input controls such as RadioButtonList.济南大学毕业设计外文资料翻译-8-Validating Expressions:The RegularExpressionValidator Control You can use RegularExpressionValidator to match the value entere
48、d into a form field to a regular expression.You can use this control to check whether a user has entered,for example,a valid e-mail address,telephone number,or username or password.Samples of how to use a regular expression to perform all these validation tasks are provided in the following sections
49、.Comparing Values:The CompareValidator Control The CompareValidator control performs comparisons between the data entered into a form field and another value.The other value can be a fixed value,such as a particular number,or a value entered into another control.Summarizing Errors:The ValidationSumm
50、ary Control Imagine that you have a form with 50 form fields.If you use only the Validation controls discussed in the previous sections of this chapter to display errors,seeing an error message on the page might be difficult.For example,you might have to scroll down to the 48th form field to find th