计算机论文中英文翻译

1Asp.netOverviewWhenASPwasfirstreleased,WebprogrammingwasmoredifficultbecauseyouneededIIStoserveyourASPpages.Later,ASP.NET2.0andVisualStudio®2005madeeverythingeasierbyintroducingtheWebsitemodelofdevelopment.InsteadofcreatinganewprojectinsideVisualStudio,theWebsitemodelletsyoupointtoadirectoryandstartwritingpagesandcode.Furthermore,youcanquicklytestyoursitewiththebuilt-inASP.NETDevelopmentServer,whichhostsASP.NETinalocalprocessandobviatestheneedtoinstallIIStobegindeveloping.wewillintroduceasp.net2.0technologyfromdifferentaspects.1.The.NETFrameworkClassLibraryASP.NETispartofMicrosoft'soverall.NETframework,whichcontainsavastsetofprogrammingclassesdesignedtosatisfyanyconceivableprogrammingneed.BecauseVisualBasic,JScript,andC++.Agreatdealofthefunctionalityoftheseprogramminglanguagesoverlaps.Forexample,foreachlanguage,youwouldhavetoincludemethodsforaccessingthefilesystem,workingwithdatabases,andmanipulatingstrings.What’smore,theselanguagescontainsimilarprogrammingconstructs,canrepresentloopsandconditionals.EventhoughthesyntaxofaconditionalwritteninVisualBasicdiffersfromthesyntaxofaconditionalwritteninC++,theprogrammingfunctionisthesame.Maintainingallthisfunctionalityformultiplelanguagesrequiresalotofwork.Wouldn'titbeeasiertocreateallthisfunctionalityonceanduseitforeverylanguage?However,The.NETFrameworkClassLibrarydoesexactlythat.Itconsistsofavastsetofclassesdesignedtosatisfyanyconceivableprogrammingneed.Forinstance,the.NETframeworkcontainsclassesforhandlingdatabaseaccess,workingwiththefilesystem,manipulatingtext,andgeneratinggraphics.Inaddition,itcontainsmorespecializedclassesforperformingtaskssuchasworkingwithregularexpressionsandhandlingnetworkprotocols.Furthermore,the.NETframeworkcontainsclassesthatrepresentallthebasicvariabledatatypessuchasstrings,integers,bytes,characters,andarrays.2The.NETframeworkishuge.Itcontainsthousandsofclasses(over3,400).Fortunately,theclassesarenotsimplyjumbledtogether.Theclassesofthe.NETframeworkareorganizedintoahierarchyofnamespaces.Anamespaceisalogicalgroupingofclasses.Forexample,alltheclassesthatrelatetoworkingwiththefilesystemaregatheredtogetherintotheSystem.IOnamespace.Thenamespacesareorganizedintoahierarchy(alogicaltree).AttherootofthetreeistheSystemnamespace.Thisnamespacecontainsalltheclassesforthebasedatatypes,suchasstringsandarrays.Italsocontainsclassesforworkingwithrandomnumbersanddatesandtimes.Youcanuniquelyidentifyanyclassinthe.NETframeworkbyusingthefullnamespaceoftheclass.Forexample,touniquelyrefertotheclassthatrepresentsafilesystemfile(theFileclass),youwouldusethefollowing:System.IO.FileSystem.IOreferstothenamespace,andFilereferstotheparticularclass.TheclassescontainedinaselectnumberofnamespacesareavailableinyourASP.NETpagesbydefault.(Youmustexplicitlyimportothernamespaces.)ThesedefaultnamespacescontainclassesthatyouusemostofteninyourASP.NETapplications:System—Containallthebasedatatypesandotherusefulclassessuchasthoserelatedtogeneratingrandomnumbersandworkingwithdatesandtimes.System.Collections—Containsclassesforworkingwithstandardcollectiontypessuchashashtables,andarraylists.System.Collections.Specialized—Containsclassesthatrepresentspecializedcollectionssuchaslinkedlistsandstringcollections.System.Configuration—Containsclassesforworkingwithconfigurationfiles(Web.configfiles).System.Text—Containsclassesforencoding,decoding,andmanipulatingthecontentsofstrings.System.Text.RegularExpressions—Containsclassesforperformingregularexpressionmatchandreplaceoperations.3System.Web—ContainthebasicclassesforworkingwiththeWorldWideWeb,includingclassesforrepresentingbrowserrequestsandserverresponses.System.Web.Caching—Containsclassesusedforcachingthecontentofpagesandclassesforperformingcustomcachingoperations.System.Web.Security—ContainsclassesforimplementingauthenticationandauthorizationsuchasFormsandPassportauthentication.System.Web.SessionState—Containsclassesforimplementingsessionstate.System.Web.UI—ContainthebasicclassesusedinbuildingtheuserinterfaceofASP.NETpages.System.Web.UI.HTMLControls—ContaintheclassesfortheHTMLcontrols.System.Web.UI.WebControls—ContaintheclassesfortheWebcontrols.YoucanchooseC#orJScript.NETorC++orVisualBasictoprogramasp.netpage.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,thecla