ASP编程：Using the Counters Object （1）
无法实现跨操作系统的应用。当然这也是微软的理由之一，只有这样才能发挥ASP最佳的能力。可是我却认为正是Windows限制了ASP，ASP的概念本就是为一个能让系统运行于一个大的多样化环境而设计的；objectIntroduction:Inyesterdaysarticle,RecordingPageHitswithMicrosoftsPageCounterObjectweexaminedusingMicrosoftsPageCounterobjecttotrackthenumberofhitsforanyparticularWebpage.Unfortunatelythiscomponentisonlybuiltforcountingpageviewhits.Ifwewantedtocountsomethingelse,sayeachtimeauserenteredaparticularsearchqueryintooursitessearchpage,wedbehardpressedwithusingthePageCounterobject.FortunatelyMicrosoftalsoprovidesdeveloperswithamoregenericcountingobject,theCountersobject.Thisobjectcanbeusedtotrackanindeterminentnumberofdeveloper-definedcounters.
BoththePageCounterandCounterscomponentsaremadeavailablewithMicrosoftsIISResourceKit.UnfortunatelythereisshoddydocumentationfortheIISResourceKit-itseemstobeisntalledonIIS5(Windows2000)bydefault,butolderversionsofIISmaynothaveitproperlyinstalled.Refertothepreviousarticle,RecordingPageHitswithMicrosoftsPageCounterObject,formoreinformationontheIISResourceKitandhowtoobtainitifyoudonthaveitinstalled.
AssumingyouhavetheIISResourceKitcomponentsproperlyinstalledyoushouldbeabletocreateaninstanceoftheCountersobjectusingthefollowingcode:
<%Setobj=Server.CreateObject("MSWC.Counters")%>
IfyougetaServer.CreateObjectFailed,Invalidclassstringerrorthenthecomponentsarenotproperlyinstalled.(IfthisisthecaseyoushouldtrychangingMSWC.CounterstoIISSample.Countersandcrossyourfingers.)Ifyoureceivenosucherrormessagethenthecomponentisproperlyinstalled.
UsingtheCountersObject:
TheCountersobjectallowsyoutocreateanynumberofpersistentcounters.WhenusingtheCountersobjectitissmartesttocreateasinlgeapplication-wideinstanceofthisobject.WecanmosteasilydothisbyaddingthefollowinglinetothetopofourGlobal.asafile:
<OBJECTRUNAT=ServerSCOPE=ApplicationID=objCounterPROGID="MSWC.Counters"></OBJECT>
TolearnmoreaboutGlobal.asabesuretoread:EverythingyouWantedtoKnowaboutGlobal.asabutwereafraidtoAskandGlobal.asaEventsaswellastheCreatingaGlobal.asaFilesectionofthesamplechapterofSamsTeachYourselfASP3.0in21Days!
OncethislineisaddedtoGlobal.asayoucanaccesstheCountersobjectfromanyASPpageinyourWebsitebytheobjectsIDthatwespecifiedintheOBJECTtag:objCounter.LikethePageCounterobjectdiscussedinyesterdaysarticle,theCountersobjectisafairlysimpleobjectconsistingofonlyfourmethods:
Get(CounterName)-RetrievesthecurrentvalueofthecounterspecifiedbythenameCounterName
Increment(CounterName)-IncrementsthecurrentvalueofthecounterspecifiedbythenameCounterName
Remove(CounterName)-RemovesthecounterspecifiedbythenameCounterNamefromthetextfilecounters.txt.Thistextfileiswherethecounterinformationispersisted.
Set(CounterName,Value)-SetsthevalueofthecounterspecifiedbythenameCounterNametothevaluespecifiedbyValue
So,oncewehaveaddedtheOBJECTtagabovetoourGlobal.asafilewecanstartworkingwiththeCountersobjectfromanyASPpageonourWebsite.WecouldusetheCountersobjectmuchlikeweusedthePageCounterobject.Forexample,ifwewantedtocreateacountertoseehowmanyfolksvisitedourhomepagewecouldusethefollowingcodeonourhomepage:
<%
Incrementthehomepagecounter
objCounter.Increment("HomePage")
Displayhowmanyhitswevehad
Response.Write"Therehavebeen"&objCounter.Get("HomePage")&"hits."
%>
ThecounternameHomePagedoesntrepresentanyspecialsortofname.Youcansimplycreateacounterbyspecifyingauniquename.Oncethecounteriscreatedyoucanincrementit,changeit,getitscurrentvalue,orremoveitfromanypageonyourWebsite.So,ifonanotherpageyouhadthesamecodeasaboveandtenvisitorshityourhomepageandthenfivevisitorshitthissecondpage,thevaluefortheHomePagecounterwillbe15-10hitsfromthehomepageand5hitsfromthesecondarypage.
InPart2wellexaminetheCountersobjectinmoredetail,lookingathowandwhereitsvaluesarepersisted.Wellalsolookatsomecodetodisplayallofthevaluesofthevariouscounterswemayhavecreated!
</p>asp可以轻松地实现对页面内容的动态控制，根据不同的浏览者，显示不同的页面内容。而浏览者一点觉察不出来，就像为他专门制作的页面一样。使用各种各样的组件，asp可以完成无比强大的功能。 另外因为asp需要使用组件，所以了解一点组件的知识(ADODB也是组件) 我想问如何掌握学习节奏(先学什么再学什么)最好详细点? 虽然ASP也有很多网络教程。但是这些都不系统。都是半路出家，只是从一个例子告诉你怎么用。不会深入讨论，更不会将没有出现在例子里的方法都一一列举出来。 以HTML语言整合(HTML负责界面上，ASP则负责功能上)形成一个B/S(浏览器/服务器)模式的网页程序。 完全不知道到底自己学的是什么。最后，除了教程里面说的几个例子，还是什么都不会。 Request:从字面上讲就是“请求”，因此这个是处理客户端提交的东东的,例如Resuest.Form，Request.QueryString,或者干脆Request("变量名") 弱类型造成潜在的出错可能：尽管弱数据类型的编程语言使用起来回方便一些，但相对于它所造成的出错几率是远远得不偿失的。 从事这个行业，那么你可以学ASP语言，简单快速上手，熟练dreamweav排版，写asp代码，熟练photoshop处理图片，打好基础就行了
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