毕业论文英文文献及翻译.docx

毕业论文英文文献及翻译.docx

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毕业论文英文文献及翻译

英文原文

ASP.NETandthe.NETFramework

ASP.NETispartofMicrosoft'soverall.NETframework,whichcontainsavastsetofprogrammingclassesdesignedtosatisfyanyconceivableprogrammingneed.Inthefollowingtwosections,youlearnhowASP.NETfitswithinthe.NETframework,andyoulearnaboutthelanguagesyoucanuseinyourASP.NETpages.

The.NETFrameworkClassLibrary

ImaginethatyouareMicrosoft.Imaginethatyouhavetosupportmultipleprogramminglanguages—suchasVisualBasic,JScript,andC++.Agreatdealofthefunctionalityoftheseprogramminglanguagesoverlaps.Forexample,foreachlanguage,youwouldhavetoincludemethodsforaccessingthefilesystem,workingwithdatabases,andmanipulatingstrings.

Furthermore,theselanguagescontainsimilarprogrammingconstructs.Everylanguage,forexample,canrepresentloopsandconditionals.EventhoughthesyntaxofaconditionalwritteninVisualBasicdiffersfromthesyntaxofaconditionalwritteninC++,theprogrammingfunctionisthesame.

Finally,mostprogramminglanguageshavesimilarvariabledatatypes.Inmostlanguages,youhavesomemeansofrepresentingstringsandintegers,forexample.Themaximumandminimumsizeofanintegermightdependonthelanguage,butthebasicdatatypeisthesame.

Maintainingallthisfunctionalityformultiplelanguagesrequiresalotofwork.Whykeepreinventingthewheel?

Wouldn'titbeeasiertocreateallthisfunctionalityonceanduseitforeverylanguage?

The.NETFrameworkClassLibrarydoesexactlythat.Itconsistsofavastsetofclassesdesignedtosatisfyanyconceivableprogrammingneed.Forexample,the.NETframeworkcontainsclassesforhandlingdatabaseaccess,workingwiththefilesystem,manipulatingtext,andgeneratinggraphics.Inaddition,itcontainsmorespecializedclassesforperformingtaskssuchasworkingwithregularexpressionsandhandlingnetworkprotocols.

 The.NETframework,furthermore,containsclassesthatrepresentallthebasicvariabledatatypessuchasstrings,integers,bytes,characters,andarrays.

Mostimportantly,forpurposesofthisbook,the.NETFrameworkClassLibrarycontainsclassesforbuildingASP.NETpages.Youneedtounderstand,however,thatyoucanaccessanyofthe.NETframeworkclasseswhenyouarebuildingyourASP.NETpages.

UnderstandingNamespaces

Asyoumightguess,the.NETframeworkishuge.Itcontainsthousandsofclasses（over3,400）.Fortunately,theclassesarenotsimplyjumbledtogether.Theclassesofthe.NETframeworkareorganizedintoahierarchyofnamespaces.

ASPClassicNote

InpreviousversionsofActiveServerPages,youhadaccesstoonlyfivestandardclasses（theResponse,Request,Session,Application,andServerobjects）.ASP.NET,incontrast,providesyouwithaccesstoover3,400classes!

Anamespaceisalogicalgroupingofclasses.Forexample,alltheclassesthatrelatetoworkingwiththefilesystemaregatheredtogetherintotheSystem.IOnamespace.

Thenamespacesareorganizedintoahierarchy（alogicaltree）.AttherootofthetreeistheSystemnamespace.Thisnamespacecontainsalltheclassesforthebasedatatypes,suchasstringsandarrays.Italsocontainsclassesforworkingwithrandomnumbersanddatesandtimes.

Youcanuniquelyidentifyanyclassinthe.NETframeworkbyusingthefullnamespaceoftheclass.Forexample,touniquelyrefertotheclassthatrepresentsafilesystemfile（theFileclass）,youwouldusethefollowing:

System.IO.File

System.IOreferstothenamespace,andFilereferstotheparticularclass.

NOTE

Youcanviewallthenamespacesofthestandardclassesinthe.NETFrameworkClassLibrarybyviewingtheReferenceDocumentationforthe.NETFramework.

StandardASP.NETNamespaces

TheclassescontainedinaselectnumberofnamespacesareavailableinyourASP.NETpagesbydefault.（Youmustexplicitlyimportothernamespaces.）ThesedefaultnamespacescontainclassesthatyouusemostofteninyourASP.NETapplications:

System—Containsallthebasedatatypesandotherusefulclassessuchasthoserelatedtogeneratingrandomnumbersandworkingwithdatesandtimes.

System.Collections—Containsclassesforworkingwithstandardcollectiontypessuchashashtables,andarraylists.

System.Collections.Specialized—Containsclassesthatrepresentspecializedcollectionssuchaslinkedlistsandstringcollections.

System.Configuration—Containsclassesforworkingwithconfigurationfiles（Web.configfiles）.

System.Text—Containsclassesforencoding,decoding,andmanipulatingthecontentsofstrings.

System.Text.RegularExpressions—Containsclassesforperformingregularexpressionmatchandreplaceoperations.

System.Web—ContainsthebasicclassesforworkingwiththeWorldWideWeb,includingclassesforrepresentingbrowserrequestsandserverresponses.

System.Web.Caching—Containsclassesusedforcachingthecontentofpagesandclassesforperformingcustomcachingoperations.

System.Web.Security—ContainsclassesforimplementingauthenticationandauthorizationsuchasFormsandPassportauthentication.

System.Web.SessionState—Containsclassesforimplementingsessionstate.

System.Web.UI—ContainsthebasicclassesusedinbuildingtheuserinterfaceofASP.NETpages.

System.Web.UI.HTMLControls—ContainstheclassesfortheHTMLcontrols.

System.Web.UI.WebControls—ContainstheclassesfortheWebcontrols.

.NETFramework-CompatibleLanguages

Forpurposesofthisbook,youwillwritetheapplicationlogicforyourASP.NETpagesusingVisualBasicasyourprogramminglanguage.ItisthedefaultlanguageforASP.NETpages（andthemostpopularprogramminglanguageintheworld）.AlthoughyousticktoVisualBasicinthisbook,youalsoneedtounderstandthatyoucancreateASP.NETpagesbyusinganylanguagethatsupportsthe.NETCommonLanguageRuntime.Outofthebox,thisincludesC#（pronouncedSeeSharp）,JScript.NET（the.NETversionofJavaScript）,andtheManagedExtensionstoC++.

NOTE

TheCDincludedwiththisbookcontainsC#versionsofallthecodesamples.

DozensofotherlanguagescreatedbycompaniesotherthanMicrosofthavebeendevelopedtoworkwiththe.NETframework.SomeexamplesoftheseotherlanguagesincludePython,SmallTalk,Eiffel,andCOBOL.Thismeansthatyoucould,ifyoureallywantedto,writeASP.NETpagesusingCOBOL.

RegardlessofthelanguagethatyouusetodevelopyourASP.NETpages,youneedtounderstandthatASP.NETpagesarecompiledbeforetheyareexecuted.ThismeansthatASP.NETpagescanexecuteveryquickly.

ThefirsttimeyourequestanASP.NETpage,thepageiscompiledintoa.NETclass,andtheresultingclassfileissavedbeneathaspecialdirectoryonyourservernamedTemporaryASP.NETFiles.ForeachandeveryASP.NETpage,acorrespondingclassfileappearsintheTemporaryASP.NETFilesdirectory.WheneveryourequestthesameASP.NETpageinthefuture,thecorrespondingclassfileisexecuted.

WhenanASP.NETpageiscompiled,itisnotcompileddirectlyintomachinecode.Instead,itiscompiledintoanintermediate-levellanguagecalledMicrosoftIntermediateLanguage（MSIL）.All.NET-compatiblelanguagesarecompiledintothisintermediatelanguage.

AnASP.NETpageisn'tcompiledintonativemachinecodeuntilitisactuallyrequestedbyabrowser.Atthatpoint,theclassfilecontainedintheTemporaryASP.NETFilesdirectoryiscompiledwiththe.NETframeworkJustinTime（JIT）compilerandexecuted.

Themagicalaspectofthiswholeprocessisthatithappensautomaticallyinthebackground.AllyouhavetodoiscreateatextfilewiththesourcecodeforyourASP.NETpage,andthe.NETframeworkhandlesallthehardworkofconvertingitintocompiledcodeforyou.

ASPCLASSICNOTE

WhataboutVBScript?

BeforeASP.NET,VBScriptwasthemostpopularlanguagefordevelopingActiveServerPages.

ASP.NETdoesnotsupportVBScript,andthisisgoodnews.VisualBasicisasupersetofVBScript,whichmeansthatVisualBasichasallthefunctionalityofVBScriptandmore.So,youhavearichersetoffunctionsandstatementswithVisualBasic.

Furthermore,unlikeVBScript,VisualBasicisacompiledlanguage.ThismeansthatifyouuseVisualBasictorewritethesamecodethatyouwrotewithVBScript,youcangetbetterperformance.

IfyouhaveworkedonlywithVBScriptandnotVisualBasicinthepast,don'tworry.SinceVBScriptissocloselyrelatedtoVisualBasic,you'llfinditeasytomakethetransitionbetweenthetwolanguages.

NOTEMicrosoftincludesaninterestingtoolnamedtheILDisassembler（ILDASM）withthe.NETframework.YoucanusethistooltoviewthedisassembledcodeforanyoftheASP.NETclassesintheTemporaryASP.NETFilesdirectory.Itlistsallthemethodsandpropertiesoftheclassandenablesyoutoviewtheintermediate-levelcode.

ThistoolalsoworkswithalltheASP.NETcontrolsdiscussedinthischapter.Forexample,youcanusetheILDisassemblertoviewtheintermediate-levelcodefortheTextBoxcontrol（locatedinafilenamedSystem.Web.dll）.

中文翻译

ASP.NET和.NETFramework

ASP.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