ASP毕业设计外文翻译3

1、asp.net asp.net 是一个统一的 web 开发模型，它包括您使用尽可能少的代码生成企业级 web 应用程序所必需的各种服务。asp.net 作为 .net framework 的一部分提供。当您编写 asp.net 应用程序的代码时，可以访问 .net framework 中的类。您可以使用与公共语言运行库 (clr) 兼容的任何语言来编写应用程序的代码，这些语言包括 microsoft visual basic、c#、jscript .net 和 j#。使用这些语言，可以开发利用公共语言运行库、类型安全、继承等方面的优点的 asp.net 应用程序。asp.net 包括： 页和控

2、件框架 asp.net 编译器 安全基础结构 状态管理功能 应用程序配置 运行状况监视和性能功能 调试支持 xml web services 框架 可扩展的宿主环境和应用程序生命周期管理 可扩展的设计器环境asp.net 页和控件框架是一种编程框架，它在 web 服务器上运行，可以动态地生成和呈现 asp.net 网页。可以从任何浏览器或客户端设备请求 asp.net 网页，asp.net 会向请求浏览器呈现标记（例如 html）。通常，您可以对多个浏览器使用相同的页，因为 asp.net 会为发出请求的浏览器呈现适当的标记。但是，您可以针对诸如 microsoft internet expl

3、orer 6 的特定浏览器设计 asp.net 网页，并利用该浏览器的功能。asp.net 支持基于 web 的设备（如移动电话、手持型计算机和个人数字助理 (pda)）的移动控件。 asp.net 网页是完全面向对象的。在 asp.net 网页中，可以使用属性、方法和事件来处理 html 元素。asp.net 页框架为响应在服务器上运行的代码中的客户端事件提供统一的模型，从而使您不必考虑基于 web 的应用程序中固有的客户端和服务器隔离的实现细节。该框架还会在页处理生命周期中自动维护页及该页上控件的状态。使用 asp.net 页和控件框架还可以将常用的 ui 功能封装成易于使用且可重用的控件

4、。控件只需编写一次，即可用于许多页并集成到 asp.net 网页中。这些控件在呈现期间放入 asp.net 网页中。asp.net 页和控件框架还提供各种功能，以便可以通过主题和外观来控制网站的整体外观和感觉。可以先定义主题和外观，然后在页面级或控件级应用这些主题和外观。除了主题外，还可以定义母版页，以使应用程序中的页具有一致的布局。一个母版页可以定义您希望应用程序中的所有页（或一组页）所具有的布局和标准行为。然后可以创建包含要显示的页特定内容的各个内容页。当用户请求内容页时，这些内容页与母版页合并，产生将母版页的布局与内容页中的内容组合在一起的输出。所有 asp.net 代码都经过了编译，可

5、提供强类型、性能优化和早期绑定以及其他优点。代码一经编译，公共语言运行库会进一步将 asp.net 编译为本机代码，从而提供增强的性能。asp.net 包括一个编译器，该编译器将包括页和控件在内的所有应用程序组件编译成一个程序集，之后 asp.net 宿主环境可以使用该程序集来处理用户请求。除了 .net 的安全功能外，asp.net 还提供了高级的安全基础结构，以便对用户进行身份验证和授权，并执行其他与安全相关的功能。您可以使用由 iis 提供的 windows 身份验证对用户进行身份验证，也可以通过您自己的用户数据库使用 asp.net forms 身份验证和 asp.net 成员资格来管

6、理身份验证。此外，可以使用 windows 组或您自己的自定义角色数据库（使用 asp.net 角色）来管理 web 应用程序的功能和信息方面的授权。您可以根据应用程序的需要方便地移除、添加或替换这些方案。asp.net 始终使用特定的 windows 标识运行，因此，您可以通过使用 windows 功能（例如 ntfs 访问控制列表 (acl)、数据库权限等等）来保护应用程序的安全。asp.net 提供了内部状态管理功能，它使您能够存储页请求期间的信息，例如客户信息或购物车的内容。您可以保存和管理应用程序特定、会话特定、页特定、用户特定和开发人员定义的信息。此信息可以独立于页上的任何控件。a

7、sp.net 提供了分布式状态功能，使您能够管理一台计算机或数台计算机上同一应用程序的多个实例的状态信息。通过 asp.net 应用程序使用的配置系统，可以定义 web 服务器、网站或单个应用程序的配置设置。您可以在部署 asp.net 应用程序时定义配置设置，并且可以随时添加或修订配置设置，且对运行的 web 应用程序和服务器具有最小的影响。asp.net 配置设置存储在基于 xml 的文件中。由于这些 xml 文件是 ascii 文本文件，因此对 web 应用程序进行配置更改比较简单。您可以扩展配置方案，使其符合自己的要求。asp.net 包括可监视 asp.net 应用程序的运行状况和性

8、能的功能。使用 asp.net 运行状况监视可以报告关键事件，这些关键事件提供有关应用程序的运行状况和错误情况的信息。这些事件显示诊断和监视特征的组合，并在记录哪些事件以及如何记录事件等方面提供了高度的灵活性。asp.net 支持两组可供应用程序访问的性能计数器： asp.net 系统性能计数器组 asp.net 应用程序性能计数器组asp.net 利用运行库调试基础结构来提供跨语言和跨计算机调试支持。可以调试托管和非托管对象，以及公共语言运行库和脚本语言支持的所有语言。此外，asp.net 页框架提供使您可以将检测消息插入 asp.net 网页的跟踪模式。asp.net 支持 xml web

9、 services。xml web services 是包含业务功能的组件，利用该业务功能，应用程序可以使用 http 和 xml 消息等标准跨越防火墙交换信息。xml web services 不用依靠特定的组件技术或对象调用约定。因此，用任何语言编写、使用任何组件模型并在任何操作系统上运行的程序，都可以访问 xml web services。asp.net 包括一个可扩展的宿主环境，该环境控制应用程序的生命周期，即从用户首次访问此应用程序中的资源（例如页）到应用程序关闭这一期间。虽然 asp.net 依赖作为应用程序宿主的 web 服务器 (iis)，但 asp.net 自身也提供了许多宿

10、主功能。通过 asp.net 的基础结构，您可以响应应用程序事件并创建自定义 http 处理程序和 http 模块。asp.net 中提供了对创建 web 服务器控件设计器（用于可视化设计工具，例如 visual studio）的增强支持。使用设计器可以为控件生成设计时用户界面，这样开发人员可以在可视化设计工具中配置控件的属性和内容。c# 是一种简洁、类型安全的面向对象的语言，开发人员可以使用它来构建在 .net framework 上运行的各种安全、可靠的应用程序。使用 c#，您可以创建传统的 windows 客户端应用程序、xml web services、分布式组件、客户端 - 服务器应

11、用程序、数据库应用程序以及很多其他类型的程序。microsoft visual c# 2005 提供高级代码编辑器、方便的用户界面设计器、集成调试器和许多其他工具，以在 c# 语言版本 2.0 和 .net framework 的基础上加快应用程序的开发。c# 语法表现力强，只有不到 90 个关键字，而且简单易学。c# 的大括号语法使任何熟悉 c、c+ 或 java 的人都可以立即上手。了解上述任何一种语言的开发人员通常在很短的时间内就可以开始使用 c# 高效地工作。c# 语法简化了 c+ 的诸多复杂性，同时提供了很多强大的功能，例如可为空的值类型、枚举、委托、匿名方法和直接内存访问，这些都是

12、 java 所不具备的。c# 还支持泛型方法和类型，从而提供了更出色的类型安全和性能。c# 还提供了迭代器，允许集合类的实现者定义自定义的迭代行为，简化了客户端代码对它的使用。作为一种面向对象的语言，c# 支持封装、继承和多态性概念。所有的变量和方法，包括 main 方法（应用程序的入口点），都封装在类定义中。类可能直接从一个父类继承，但它可以实现任意数量的接口。重写父类中的虚方法的各种方法要求 override 关键字作为一种避免意外重定义的方式。在 c# 中，结构类似于一个轻量类；它是一种堆栈分配的类型，可以实现接口，但不支持继承。除了这些基本的面向对象的原理，c# 还通过几种创新的语言结

13、构加快了软件组件的开发，其中包括： 封装的方法签名（称为委托），它实现了类型安全的事件通知。 属性 (property)，充当私有成员变量的访问器。 属性 (attribute)，提供关于运行时类型的声明性元数据。 内联 xml 文档注释。在 c# 中，如果需要与其他 windows 软件（如 com 对象或本机 win32 dll）交互，可以通过一个称为“interop”的过程来实现。互操作使 c# 程序能够完成本机 c+ 应用程序可以完成的几乎任何任务。在直接内存访问必不可少的情况下，c# 甚至支持指针和“不安全”代码的概念。c# 的生成过程比 c 和 c+ 简单，比 java 更为灵活。

14、没有单独的头文件，也不要求按照特定顺序声明方法和类型。c# 源文件可以定义任意数量的类、结构、接口和事件。c# 程序在 .net framework 上运行，它是 windows 的一个必要组件，包括一个称为公共语言运行时 (clr) 的虚拟执行系统和一组统一的类库。clr 是 microsoft 的公共语言基础结构 (cli) 的一个商业实现。cli 是一种国际标准，是用于创建语言和库在其中无缝协同工作的执行和开发环境的基础。用 c# 编写的源代码被编译为一种符合 cli 规范的中间语言 (il)。il 代码与资源（如位图和字符串）一起作为一种称为程序集的可执行文件存储在磁盘上，通常具有的扩

15、展名为 .exe 或 .dll。程序集包含清单，它提供关于程序集的类型、版本、区域性和安全要求等信息。执行 c# 程序时，程序集将加载到 clr 中，这可能会根据清单中的信息执行不同的操作。然后，如果符合安全要求，clr 执行实时 (jit) 编译以将 il 代码转换为本机机器指令。clr 还提供与自动垃圾回收、异常处理和资源管理有关的其他服务。由 clr 执行的代码有时称为“托管代码”，它与编译为面向特定系统的本机机器语言的“非托管代码”相对应。下图演示了 c# 源代码文件、基类库、程序集和 clr 的编译时与运行时的关系。语言互操作性是 .net framework 的一个关键功能。因为由

16、 c# 编译器生成的 il 代码符合公共类型规范 (cts)，因此从 c# 生成的 il 代码可以与从 visual basic、visual c+、visual j# 的 .net 版本或者其他 20 多种符合 cts 的语言中的任何一种生成的代码进行交互。单一程序集可能包含用不同 .net 语言编写的多个模块，并且类型可以相互引用，就像它们是用同一种语言编写的。除了运行时服务，.net framework 还包含一个由 4000 多个类组成的内容详尽的库，这些类被组织为命名空间，为从文件输入和输出到字符串操作、到 xml 分析、到 windows 窗体控件的所有内容提供多种有用的功能。典型

17、的 c# 应用程序使用 .net framework 类库广泛地处理常见的“日常”任务。asp.netasp.net is a unified web development model that includes the services necessary for you to build enterprise-class web applications with a minimum of coding. asp.net is part of the .net framework, and when coding asp.net applications you have access

18、to classes in the .net framework. you can code your applications in any language compatible with the common language runtime (clr), including microsoft visual basic, c#, jscript.net, and j#. these languages enable you to develop asp.net applications that benefit from the common language runtime, typ

19、e safety, inheritance, and so on.asp.net includes: a page and controls framework the asp.net compiler security infrastructure state-management facilities application configuration health monitoring and performance features debugging support an xml web services framework extensible hosting environmen

20、t and application life cycle management an extensible designer environmentthe asp.net page and controls framework is a programming framework that runs on a web server to dynamically produce and render asp.net web pages. asp.net web pages can be requested from any browser or client device, and asp.ne

21、t renders markup (such as html) to the requesting browser. as a rule, you can use the same page for multiple browsers, because asp.net renders the appropriate markup for the browser making the request. however, you can design your asp.net web page to target a specific browser, such as microsoft inte

22、rnet explorer 6, and take advantage of the features of that browser. asp.net supports mobile controls for web-enabled devices such as cellular phones, handheld computers, and personal digital assistants (pdas). asp.net web pages are completely object-oriented. within asp.net web pages you can work w

23、ith html elements using properties, methods, and events. the asp.net page framework removes the implementation details of the separation of client and server inherent in web-based applications by presenting a unified model for responding to client events in code that runs at the server. the framewor

24、k also automatically maintains the state of a page and the controls on that page during the page processing life cycle. the asp.net page and controls framework also enables you to encapsulate common ui functionality in easy-to-use, reusable controls. controls are written once, can be used in many pa

25、ges, and are integrated into the asp.net web page that they are placed in during rendering.the asp.net page and controls framework also provides features to control the overall look and feel of your web site via themes and skins. you can define themes and skins and then apply them at a page level or

26、 at a control level. in addition to themes, you can define master pages that you use to create a consistent layout for the pages in your application. a single master page defines the layout and standard behavior that you want for all the pages (or a group of pages) in your application. you can then

27、create individual content pages that contain the page-specific content you want to display. when users request the content pages, they merge with the master page to produce output that combines the layout of the master page with the content from the content page. all asp.net code is compiled, which

28、enables strong typing, performance optimizations, and early binding, among other benefits. once the code has been compiled, the common language runtime further compiles asp.net code to native code, providing improved performance.asp.net includes a compiler that will compile all your application comp

29、onents including pages and controls into an assembly that the asp.net hosting environment can then use to service user requests. in addition to the security features of .net, asp.net provides an advanced security infrastructure for authenticating and authorizing user access as well as performing oth

30、er security-related tasks. you can authenticate users using windows authentication supplied by iis, or you can manage authentication using your own user database using asp.net forms authentication and asp.net membership. additionally, you can manage the authorization to the capabilities and informat

31、ion of your web application using windows groups or your own custom role database using asp.net roles. you can easily remove, add to, or replace these schemes depending upon the needs of your application. asp.net always runs with a particular windows identity so you can secure your application using

32、 windows capabilities such as ntfs access control lists (acls), database permissions, and so on. for more information on the identity of asp.net,asp.net provides intrinsic state management functionality that enables you to store information between page requests, such as customer information or the

33、contents of a shopping cart. you can save and manage application-specific, session-specific, page-specific, user-specific, and developer-defined information. this information can be independent of any controls on the page.asp.net offers distributed state facilities, which enable you to manage state

34、information across multiple instances of the same application on one computer or on several computers. asp.net applications use a configuration system that enables you to define configuration settings for your web server, for a web site, or for individual applications. you can make configuration set

35、tings at the time your asp.net applications are deployed and can add or revise configuration settings at any time with minimal impact on operational web applications and servers. asp.net configuration settings are stored in xml-based files. because these xml files are ascii text files, it is simple

36、to make configuration changes to your web applications. you can extend the configuration scheme to suit your requirements. asp.net includes features that enable you to monitor health and performance of your asp.net application. asp.net health monitoring enables reporting of key events that provide i

37、nformation about the health of an application and about error conditions. these events show a combination of diagnostics and monitoring characteristics and offer a high degree of flexibility in terms of what is logged and how it is logged. asp.net supports two groups of performance counters accessib

38、le to your applications: the asp.net system performance counter group the asp.net application performance counter groupasp.net takes advantage of the run-time debugging infrastructure to provide cross-language and cross-computer debugging support. you can debug both managed and unmanaged objects, as

39、 well as all languages supported by the common language runtime and script languages. in addition, the asp.net page framework provides a trace mode that enables you to insert instrumentation messages into your asp.net web pages. asp.net supports xml web services. an xml web service is a component co

40、ntaining business functionality that enables applications to exchange information across firewalls using standards like http and xml messaging. xml web services are not tied to a particular component technology or object-calling convention. as a result, programs written in any language, using any co

41、mponent model, and running on any operating system can access xml web services. asp.net includes an extensible hosting environment that controls the life cycle of an application from when a user first accesses a resource (such as a page) in the application to the point at which the application is sh

42、ut down. while asp.net relies on a web server (iis) as an application host, asp.net provides much of the hosting functionality itself. the architecture of asp.net enables you to respond to application events and create custom http handlers and http modules. asp.net includes enhanced support for crea

43、ting designers for web server controls for use with a visual design tool such as visual studio. designers enable you to build a design-time user interface for a control, so that developers can configure your controls properties and content in the visual design tool. introduction to the c# language a

44、nd the .net framework c# is an elegant and type-safe object-oriented language that enables developers to build a wide range of secure and robust applications that run on the .net framework. you can use c# to create traditional windows client applications, xml web services, distributed components, cl

45、ient-server applications, database applications, and much, much more. microsoft visual c# 2005 provides an advanced code editor, convenient user interface designers, integrated debugger, and many other tools to facilitate rapid application development based on version 2.0 of the c# language and the

46、.net framework.note the visual c# documentation assumes that you have an understanding of basic programming concepts. if you are a complete beginner, you might want to explore visual c# express edition, which is available on the web. you can also take advantage of any of several excellent books and

47、web resources on c# to learn practical programming skills.c# syntax is highly expressive, yet with less than 90 keywords, it is also simple and easy to learn. the curly-brace syntax of c# will be instantly recognizable to anyone familiar with c, c+ or java. developers who know any of these languages

48、 are typically able to begin working productively in c# within a very short time. c# syntax simplifies many of the complexities of c+ while providing powerful features such as nullable value types, enumerations, delegates, anonymous methods and direct memory access, which are not found in java. c# a

49、lso supports generic methods and types, which provide increased type safety and performance, and iterators, which enable implementers of collection classes to define custom iteration behaviors that are simple to use by client code.as an object-oriented language, c# supports the concepts of encapsula

50、tion, inheritance and polymorphism. all variables and methods, including the main method, the applications entry point, are encapsulated within class definitions. a class may inherit directly from one parent class, but it may implement any number of interfaces. methods that override virtual methods

51、in a parent class require the override keyword as a way to avoid accidental redefinition. in c#, a struct is like a lightweight class; it is a stack-allocated type that can implement interfaces but does not support inheritance.in addition to these basic object-oriented principles, c# facilitates the

52、 development of software components through several innovative language constructs, including: encapsulated method signatures called delegates, which enable type-safe event notifications. properties, which serve as accessors for private member variables. attributes, which provide declarative metadat

53、a about types at run time. inline xml documentation comments.if you need to interact with other windows software such as com objects or native win32 dlls, you can do this in c# through a process called interop. interop enables c# programs to do just about anything that a native c+ application can do

54、. c# even supports pointers and the concept of unsafe code for those cases in which direct memory access is absolutely critical.the c# build process is simple compared to c and c+ and more flexible than in java. there are no separate header files, and no requirement that methods and types be declare

55、d in a particular order. a c# source file may define any number of classes, structs, interfaces, and events.c# programs run on the .net framework, an integral component of windows that includes a virtual execution system called the common language runtime (clr) and a unified set of class libraries.

56、the clr is microsofts commercial implementation of the common language infrastructure (cli), an international standard that is the basis for creating execution and development environments in which languages and libraries work together seamlessly.source code written in c# is compiled into an intermediate language (il) that conforms to the cli specification. the il code, along with resources such as bitmaps and strings, is stored on disk in an executable file ca