ASP.Net Unisususuususuudddususueueueueyyst-1 Ꮢ.ꪜ.pdf

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1. Jump2Learn
www.jump2learn.com PUBLICATIO
N
N
DEVELORINGWEBAPPLICATIONS
WITH
ASP.NET
Jump2LearnTheOnlineLearningPlace
LS
Ms.TwinklePanchal
|
Ms.KrishnaKhandwala
|
Mr.ChiragPrajapati

2. Unit1
Introductionto
ASP.NET

3. Unit-1Introductionta
ASP.NET
1.1WhatisASP.NET:
ASP.NETmeans"ActiveServerPages"whichisfrontendlanguage&itisestablished&
supportedbyMicrosoft.
ASP.NETisawebapplicationwhichallowstheprogrammertobuilddynamicwebsites,
Webapplications&webservices.ASP.NETallowstodevelopwebapplicationsusingafull
featuredprogramminglanguagesuchasCt,VB.NET,Jscriptor
JH
ASP.NETisawebdevelopmentplatform,whichprovidestheeasiest&mostaccessible
waytobuild,deploy&rundistributedwebapplicationswhichcantargetforanydeviceas
wellasbrowser.Inshort,ASP.NETisusedtoproduceinteractive,data-drivenweb
applicationsovertheinternet.
ASP.NETworksontopoftheHTTPprotocol,andusestheHTTPcommandsandpoliciesto
setabrowser-to-servertwo-sidedcommunicationandcooperation.
ASP.NETapplicationsarecompiledcodes,writtenusingtheextensibleandreusable
componentsorobjectspresentin.Netframework.Thesecodescanusetheentire
hierarchyofclassesin.Netframework.
ASP.NETconsistofalargenumberofcontrolssuchastextboxes,buttons,labels&many
moreforassembling,configuring&manipulatingcodetocreateHTMLpages.
AnASP.NETwebapplicationismadeofpages.WhenauserrequestsanASP.NETpage,the
IISgivestheprocessingofthepagetotheASP.NETruntimesystem.
TheASP.NETruntimetransformsthe.aspxpageintoaninstanceofaclass,whichinherits
fromthebaseclasspageoftheNetframework.Therefore,eachASP.NETpageisan
objectandallitscomponentsi.e.,theserver-sidecontrolsarealsoobjects.
1.2.NETFramework2.0:
NETisSoftwarePlatform.Itisalanguageneutralenvironmentfordeveloping
applications.Italsoprovidesanexecutionenvironmentandintegrationwithvarious
programminglanguagesforbuilding,deployingandrunningweb-basedandstandalone
enterpriseapplications.Allaspectstomanagetheprogramexecutionlikememory
allocationfordatastorageandinstructions,grantinganddenyingpermissiontothe
application,managingexecutionofapplicationandreallocationofmemoryforresources
whicharenotneededismanagedeasilyinASP.NET.Itconsistsofclasslibrariesand
reusablecomponents.
Theblockdiagramof.NETframeworkisasfollows:

4. Unit-1IntroductiontoASP.NET
VB C+ CH JScript J#
CommonLanguageSpecification
ASP.NET
Windows ADO.NET&
WebFormsWebServleesForms XML
BaseClassLibrary
CommonLanguageRuntlme
OperatingSystem
Figure1:.NETFramework
1.2.1ProgramingLanguages:
Netframeworkisdesignedforcrosslanguagecompatiblitywhichmeansitsupports
variousprograminglanguageslikeVisualBasic(VB),VisualBasic.Net(VB.Net),CH,JHetc.
Soprogrammers/developerscanchooseanyfavouriteprograminglanguagetobuildweb
application.
1.2.2CommonLanguageSpecification(CLS):
CLSisthecollectionofrulesandconstraintsthateverylanguagecompatibleto.NETmust
follow.Itisoneofthecorecomponentsofthe.NetFrameworkwhichhelpstobuild
communicationbetweendifferentcomponentswrittenindifferentprogramminglanguage
andreusethecommonlogics.MicrosofthasdefinedthreelevelofCLScompatibilityas
follow:
CompliantProducer:Thecomponentdevelopedinthistypeoflanguagecanbe
usedbyanyotherlanguage.
Consumer:Inthiscategory,thelanguagecanuseclassesproducedinanyother
language.
Extender:Inthiscategory,languagescannotuseclassesasinCONSUMERcategory
butcanalsoextendclassesusinginheritance.

5. Unit-1IntroductiontoASP.NET
1.2.3WebForms:
InASP.NET,webformsarecalledwebpageswhichhelptodevelopwebapplications.Itis
consistoftwoparts:
1.TemplatewhichcontainsHTMLbasedlayoutinformationforallGUIcontrols.
2.Componentwhichcontainsthelogicbehindthecontrols.
1.2.4WebServices:
Awebserviceisaweb-basedfunctionalitythatrunsonWebServer.Itisaccessedusing
theprotocolsofthewebtobeusedbythewebapplications.Theyarethesmallunitof
codewhichisdesigntohandlelimitedsetoftask.Theyareindependentofoperating
systemandprogramminglanguage.
1.2.5WindowForms:
WindowsFormscontainthegraphicalrepresentationofanywindowdisplayedinthe
application.ItalsoprovidesintegratedandunifiedwayofdevelopingGraphicalUser
Interface.IthasrichvarietyofwindowscontrolsanduserinterfacesupportlikeTextBox,
Button,CheckBox,etc.
WecandesigntheGUIbydraggingthecontroldirectlyonaformwhichmadeitpossible
todesignthewinformseasilyandquicklyasVisualStudio.NETusesthe'system.Winform
namespacetodrawtheGraphicalUserInterface.
1.2.6
ADO.NET&XML:
ItisthetechnologyusedforworkingwithdataanddatabaseswhichisalsoknownasData
AccessLayer.ItprovidesaccesstodatasourceslikeSQLserver,OLEDB,XMLetc.The
ADO.NETallowsconnectiontodatasourcesforretrieving,manipulating,andupdating
data.
1.2.7BaseClassLibrary(BCL):
.Netframeworkconsistsofclasses,interfacesandvaluetypesthathelpinspeedingupthe
developmentprocessandprovideaccesstothesystemfunctionality.Theclasslibraryisa
collectionofmethods&functionsthatcanbereusabletypesmeanttobeusedby
managedcode.
Itisanobject-orientedlibrarythatisusedincomponent-basedapplication.TheClass
libraryismadeupofahierarchyofnamespacesthatexposeclasses,structure,interfaces,
enumerationsanddelegates.Thenanespacesarelogicallydefinedbytheirfunctionality.
MostofthemethodsaresplitintoeitherSystem.orMicrosoft."namespaces.For

6. Unit-1IntroductiontoASP.NET
example,TheSystem.Datanamespacecontainsthefunctionalityavailableforaccessing
database.
1.2.8CommonLanguageRuntime(CLR):
Itistheruntimeenvironmentswhichdobothcompileandruntheapplication.Soitisalso
knownastheheartof.NETframework.MSIL(MicrosoftIntermediateLanguage)whichis
languageindependentcode,soCLRusesthiscodefortheexecutionoftheapplication.
TheMSILcodeistranslatedbyIT(Just-inTime)compller.
1.2.9MicrosoftIntermediateLanguage(MSIL):
ItisalsoknownasIntermediateLanguage
(1L)
orCommonIntermediateLanguage(CIL).
A.NETprogramminglanguagedoesnotcompilethecodeintoexecutablecode;insteadit
compilesthecodeintoanintermediatecodecalledMicrosoftIntermediateLanguage
(MSIL)orIntermediateLanguage(L)orCommonIntermediateLanguage(CIL).
ThisILorMSILor
CiILcodeismachineindependentcodewhichisthensendtoCLRwhich
convertsthismachineindependentcodeintonativecodewiththehelpofJIT(Just-inTime
Compiler)avalableinCLR.
1.3CompileCode:
Toservetheuserrequest,ASP.NETmustfirstcompilethecode.ASP.NETCodecanbe
writteninanylanguagesupportedby.NETframework.Whencodeiscompiled,itisfirst
convertedintoMicrosoftIndependentLanguage(MSIL).Thenthisindependentlanguageis
furtherconvertedintoMachineSpecificinstructions
BenefitsofCompiledCode:
1.Atcodecompilationtime,itischeckingforsyntaxerror,typesafetyetc.Duetowhich
manyerrorscanbeeliminatedandthatishowitgivesstabilityincodefromthelaterstage.
2.Compilecodeismuchfasterthanscriptinglanguages.Astheyaresimilartomachine
codewhichmakestheperformanceoftheexecution.
3.Compiledcodeisdifficulttoread.Sothatnoonecanconvertcompiledcodetosource
codeagainandthatishowcodebecomessecure.
4.ASMSILsupportsany.NETlanguage,weareabletouseassemblieswhicharewrittenin
differentlanguage.Forexample,ifyouarewritinganASP.NETWebpageinC4,youcanadd
areferencetoa.dllfilethatwaswritteninVisualBasic.Suchinteroperabilityfunctionalityis
alsoused.

7. 5 Unit-1IntroductiontoASP.NET
ASP.NET2.0providestwopathsforstructuringthecodofASP.NETpages:CodeBehindand
CodeInline
1.3.1CodeBehind
Inthisway,codeisseparatedfromcontentcompletelyandstoredinaseparatefile.The
ideaofusingthecodebehindistoseparatethebusinesslogictobestoredin.aspxpage
andpresentationlogictobestoredinseparateclassfileeither.aspx.vbor.aspx.cs.By
doingthis,itmakeseasytoworkwithpages.Asifyouareworkinginteamenvironment
wherevisualdesignersworkintheUlifthepageandcodersworkonthebusinesslogic.
ThisrelationshipbetweenyourclassandthewebpageisestablishedbyaPagedirectiveat
thetopofthe.aspxfile:
<%@Pageinherits="Default"%>
Theinheritsattributeidentifiestheclasscreatedinthecode-behindfilefromwhichthis
.aspxfilewillderive.
ForExample:
WebAppicEenl-McrostVesalSeude
FAlE
EEN
TELER PRCECTBRD DEBUG TEAM FORMAT TOOL5 TEST ANALYITE WDDOW
McrosotEdge
ebug
any
U
Detaut
asp.cs
Deatap
Eoedeinderauit.Esg.CSEeritsaiopiicstiond.betault
asp:{ontast=*3adCantent"Cantet?iacencide-TD»Nainantent'rurats'senver"
idfoi
runst="serve
asp:Tertšert="rareirutrinate"server"«jasp:Fertšo
5p:el
isplayruetsevefet-abel'asp:iabe)cor
sp:8uttonDSupeitrurata"serveretSbeitiickSo:tcisce
p
asp:fexttosiDTextboxtrunarserver
iasg:
Testšono
<ingutideButtonl"typewostton'valaesbutton'runate"serve
for
/asp:Content
Figure2:CodebehindPresentationLogic

8. Unit-1IntroductiontoASP.NET
ET TEuu ROnC URD cEBUGAM Toos TISTMAY wpoW
syston;
ingsyaten.celiutttons.eneric
wsiPgSyste,eb,I
Page.1skosteack)
Subndt.Teat cline
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ader.1Amernl "deBeninedl
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Subeicita(mject
ender.tAE *)
Figure3:CodebehindBusinessLogic
1.3.2InlineCoding
InlineCodeisembeddeddirectlywithintheASP.NETpagethathasanextensionof.aspx.
ItpermitsthecodetobecomposedalongwiththeHTMLsourcecodeusinga<Script>
tag.Thatmeansthebusinesslogicandthepresentationlogicarecontainedwithinthe
samefile.Whenthepageisdeployed,thesourcecodeisdeployedalongwiththeWeb
Formspage,becauseitisphysicallyinthe.aspxfile.However,youdonotseethecode,
onlytheresultsarerenderedwhenthepageruns.
ForExample:
Defsult.a
Page Title-"HomePageLanguage-"C#MasterPageFile="~/site.MasterAutoEventwireup="true
CodeBehind-"Default.aspx.cs"
Inherits="WebApp1ication-
nle ofInlineCode
protectedvoidbtnsubmit_click(objectsender,EventArgse)
if(this.txtFirstName.Text.Length=-0)
this.FirstNiameValidation.Text"FirstNoneisrequire!";
12
/script
13asp:ContentID-"BodyContent"ContentPlaceHolderID="HainContent"runat-"server
"
14asp:LabeltD»"Lableone"
Text-"First
Nane
width»"145"runat-"server">«/asp:Label»
TextBoxID="txtFirstName"runat-"server"Text"width="145">x/asp:TextBox>
ebr/»
5
br
casp:ButtonzD-"btnsubmit"runat"server"Text"Submit"onClick"btnSubmit_click"/>
<asp:LabelID="FirstNameValidation"Text=width="145"runat="server"
tyle"color:red;font-weight:5e0;"></asp:Labels
</asp:Content
Figure4:InlineCode

9. 8 Unit-1IntroductiontoASP.NET
1.4TheCommonLanguageRuntime
(CLR}:
Itisthecorecomponentof.NETFramework.ItisalsoknownasanexecutionEnvironment.
Itisusedtocompilethe
ILorMSILcodetonativecode.
FollowingdiagramshowstheworkingprocessofCLR.
C# VB.NETJC
NET
Source
Unmanagod
omponsnt
code
Compiler Compiler Compiler
ManagedAssemblylL AssemblyILAssemblyL
codeCode code
CommonLanguageRuntimeiemple
Nativecode
Operatingsyatem
Figure5:CLRExecutionModel
Themainfunctionof
CLRistoconverttheMSILcodetonativecodeandthenexecutethe
program.Themanagedcodeacodethatisdevelopedwithalanguagecompilerthat
targetsthe
CLRiscompiledonlywhenitisneeded,thatmeansitconvertstheappropriate
instructionswheneachfunctiniscalled.Theunmanagedcode
-acodethaatisdeveloped
withoutconsideringtheconventionsandrequirementsofCLR,isexecutedwithminimal
serviceofCLR.TheCLR'sJIT(Just-inTime)compilationconvertsMSILtonativecodeon
demantatapplicationrun.
Duringtheexecutionoftheprogram,theCLRprovidesfunctionalotysuchasmemory,
Debugging,ExceptionHandling,Securityandversioningsupporttoanylanguagesthat
targetit.
Inshort,When.NETprogramsareexecuted,the
CLRactivatestheJITcompiler.TheJIT
CompilerconvertsMSILintonativecodeondemandbasis.Thustheprogramexecutesasa
nativecodetoruntheprogramfast.ThatishowNETframeworkachievestheportability.
ComponentofCLR:
1.ClassLoader:Itloadstheclassesintothesystemmemoryasandwhenneeded.
2.CodeManager:ThecodemanagerinCLRmanagesthecodedevelopedinthe.NET
framework.Themanagedcodeisconvertedtointermediatelanguagebyalanguage-specific

10. Unit-1IntroductiontoASP.NET
compilerandthentheintermediatelanguage
(1L)isconvertedintothemachinecodebythe
Just-In-Time
(UIT)
compiler.
DaseCussLibrarySuppet
ThreadSupport couMarshae
TypeCrecker
Exceptinaneger
SecurityEngn DebupEngn
Llo
Nathve
Coce Gatage
Collector
CoroiorsManager
ClassLoader
Figure6:CLRComponent
8.GarbageCollection:LifetimeofanobjectismanagedbyCLRwhichperformsautomatic
memorymanagementusinggarbagecollectorinCLR.Anobjectwhichisnolongerrequired
thensuchobjectsareautomaticallyreleasingthememoryspacewithhelpofgarbage
collector.
i.MSILtoNativeCompilers:ItisusedtocompiletheMSILcodeandconvert
itintonativelanguage.
i.DebugEngine:Anapplicationcanbedebuggedduringtheruntimeusing
debugengine.
ii.SecurityEngine:In.NETarchitecture,securityisachievedwiththehelpof
theCodeAccessSecurity(CAS)mechanismwhichpreventuntrustedcode
fromperformingprivilegedactions.Thatmeans,CLRenforcesrestrictions
onmanagedcodethroughtheuseofobjectcalledpermissions.TheCLR
allowsthecodetoperformonlythosetasksforwhichithaspermission.
iv.ExceptionManager:Duringtheexecutionoftheprogram,ifany
exceptionoccursthenitishandledbyexceptionmanager.
v.TypeChecker:Objectswhichareusedinapplicationarealwaysaccessed
incompatibleways,isensuredbythisfeatureofCLR.
vi.ThreadSupport:Supportformanagingtheparallelexecutionofmultiple
threadisprovidedbyCLR.

11. 10- Unit-1IntroductiontoASP.NEI
vii.COMMarshaller:Itallowscommunicationbetweentheapplicationand
COMObjects.
vii.ClassLibrarySupport:ItprovidesBaseClassLibraryclasseswhen
applicationneedatexecutiontime.
1.5ObjectOrientedConcepts:
ObjectOrientedProgramming(OOP)isaprogrammingmodelwhereprogramsare
organizedaroundobjects,datafieldandmethodswhichinteracttodesignapplications
andcomputerprograms.
1.5.1Class:
Aclassisauser-definedprototypefromwhichobjectsarecreated.
Aclasscontainsfields
&methodsknownasmemberfunctionintosingleunit.
Syntax:
AccessModifier)<Classname>[:BaseClass|Eimplementsinterfacenames]
[Statements
Here,accessmodifiersarePublic,Private,Protectedandinternal.
ForExample:
Publicclassstudent
fields,variables,methods,properties/
1.5.2Fields:
Variablesdeclareinsideaclassarecalledfieldsthatcanbeaccessedbycreatinganobject
oftheclassandbyusingthedotsyntax().
ForExample:
PublicClassstudent
Publicintroll_no=1;
Publicstringname="Yash;
staticvoidMain(stringllargs)

12. Unit-1IntroductiontoASP.NET
studentmyStudnewstudent()
Console.Writeline{myStud.roll_no);
Console.Writeline(myStud.name);
Anotherway,todeclarefieldsandinitializethemwhilecreatingobjectswhichisvery
usefulwhenmultipleobjectsarecreated.
PublicClassstudent
Publicintroll_no;
Publicstringname;
staticvoidMain(stringllarg)
studentmyStud=newstudent();
myStud.rollno-1;
myStud.name="Yash";
Console.WriteLine(myStud.roll_no;
Console.Writeline(myStud.name);
1.5.3Properties:
Propertiesaresetandretrievedlikefields.Theyaresetofdescriptivedataofanobject
whichareimplementedusingGet&Setprocedureswhichprovidemorecontrolonhow
valuesaresetorreturned.
ForExample:
PublicClassstudent
I
Fields
privateintroll_no;
privatestringname;
properties
publicintRollNo

13. 12 Unit-1Introductlonto
ASP.NET
get
returnroll_no;
Set
roll_no=value;
publicstringStudName
Get
returnname;
Set
name=value;
staticvoidMain(stringlargs)
studentmyStud=newstudent(};
Console.WritelLine(myStud.Roll_Nol;
Console.WriteLine(myStud.StudName);
1.5.4Methods:
Amethodisablockofcodewhichonlyrunswhenitiscalled.Theyareusedtoperform
certainactions,andtheyarealsoknownasfunctionsoftheclass.
ForExample:

14. Unit-1Introductionto
ASP.NET
13
publicClassstudent
publicintroll_no-1;
publicstringname="Yash
publicvoiddisplay()
Console.Writeline(myStud.rollno);
Console.Writeline(mystud.name);
staticvoidMain(stringl]args)
studentmyStudnewstudent();
myStud.display(l
1.5.5Events:
Eventsallowsobjectstoperformanactionswheneversomespecificactiontakesplace.
Forexample,whenweclickabutton,aclickeventoccursandwecanhandlethatevent
witheventhandler.
1.5.6Objects:
ItisabasicunitofOOPwhichrepresentsrealtimeentity.Theyarecalledinstancesof
classeswhichdefinesthedata&behaviorofalltheinstancesofthattype.
ForExample:
studentmyStud=newstudent()
1.5.7Constructor:
Aconstructorisaspecialmethodusedtoinitializeobjects.Mainadvantageofa
constructoristhatitiscalledwhenanobjectofaclassiscreated.Basically,itisusedto
settheinitialvaluesofthefieldsoftheclass.
ForExample:
publicclassstudent

15. 14
Unit-1IntroductiontoASP.NET
I/fields
publicintroll_no;
publicstringname;
publicstudent()//Constructor
rollno=1;
name="Yash";
staticvoidMain(stringl
args)
studentmyStud=newstudent(};//Thiswillcalltheconstructor
Console.WritelLinefmyStud.rollno;
Console.Writeline(myStud.name);
1.5.8Destructor:
Itisexecutedautomaticallywhenanabjectisdestroyed.TheDestructoriscalledimplicitly
bythe.NETFramework'sGarbagecollectorsothatprogrammerhasnocontrolaswhento
invokethedestructor.
1.5.9Encapsulation:
Wrappingupofdatamember&memberfunctionsintosingleunitiscalledEncapsulation.
Inotherwords,Encapsulationisprotectiveshieldthatpreventsthedatafrombeing
accessedbythecodefromtheoutsideofthatshield.
So,data&membersofaclassarehiddenfromanyotherclasses.Theycanbeaccessed
onlythroughanymemberfunctionorpropertiesofownclassinwhichtheyaredeclared.
ThisconceptiscalledDataHiding.
ForExample:
publicclassstudent
privatestringname;
privateintrollno;

16. Unit-1IntroductiontoASP.NET
15
/usingpropertytogetandsetthevalueofstudentName
publicstringStudName
get
returnname;
set
name=value;
I/usingpropertytogetandsetthevalueofRolINo
publicintR_No
get
returnroll_no;
set
rollno
=value;
classStudMain
staticvoidMain(string[largs)
students=newstudent();
Icalltosetpropertywithrespectivevaluetosetstandardfield'value'
s.R_No=1;

17. 16 Unit-1IntroductiontoASP.NET
s.StudName="Yash";
/calltogetpropertyvalue
Console.Writeline(s.R_No);
Console.Writeline(s.StudNname);
1.5.10Inheritance:
Itisamechanismbywhichoneclassisallowedtoinheritthemembersofanotherclass.
Thatmeans,Inheritanceistheprocessofforminganewclassfromanexistingclass.
TheclasswhosefeaturesareinheritedisknownasParentclassorSuperclassorBase
class.TheclasswhoisacquiringthemembersofBaseclassisknownasChildclassor
DerivedclassorSubclass.Thesubclasscanadditsownfieldsandmethodsinadditionto
thesuperclassfieldsandmethods.lnheritanceisanimportantconceptofOOPasithelps
inreducingtheoverallcodesizeoftheprogramandsupportreusabilityofcode.To
inherittheclasscolon(:)symbolisused.
Syntax:
classderived-class:base-class
Imethods
andfields
ForExample:
publicclassParentClass
publicParentClass()
Console.Writeline("ParentConstructor.");
publicvoiddisplay()
Console.Writeline("T'maParentClass.");

18. Unit-1IntroductiontoASP.NET
17
publicclassChildClass:ParentClass
publicChildClass()
Console.Writeline("ChildConstructor.";
publicstaticvoidMain()
ChildClasschild=newChildClass();
child.display0;
1.5.11Abstraction:
Dataabstractionisthepropertybywhichonlyessentialandimportantinformationis
displayedtouserwithoutrepresentingbackgrounddetailswhichincreasetheefficiency.It
focusesonwhattheobjectdoesinsteadofhowitdoesit.Inotherwords,abstraction
providesageneralizedviewofclassesorobjectsbyprovidingrelevantinformation.
AbstractionisachievedwiththehelpofeitherAbstractclassesorinterfaces.The'abstract
keywordisusedforclassesandmethods.
1.5.11.1AbstractClass:
Itissuchaclasswhichcannotbeinstantiated.Thatmeans,itcannotbeusedtocreatean
objectbutitmustbeinheritedfromanotherclass.Abstractclasscanhavebothregular
andabstractmethods.
1.5.11.2AbstractMethod:
Itcanbeusedonlyinabstractclassanditdoesnothavebody.Thatmeansmethodshave
onlydeclarationinabstractclassandderivedclassmusthavetheirdefinition.'Override'
keywordisusedinderivedclasswhiledefiningtheabstractmethod.
ForExample:
abstractclassShape

19. 18 Unit-1IntroductiontoASP.NET
publicabstractintarea();
classSquare:Shape
Ilprivatedatamember
privateintside;
publicSquarelintx=0)
sid
X
publicoverrideintarea()
Console.Write("AreaofSquare:");
return(side
*side);
classProgram
staticvoidMain(stringllargs)
Squares=newSquare(4);
doubleresult=s.area()
Console.Write/"{0",result);
1.5.12Interface:
Aninterfaceissimilartoabstractclasswhichcanonlycontainabstractmethodsand
propertiesbutnotfields.Theycannotbeusedtocreateanobject.Bydefault,membersof
aninterfaceareabstractandpublic.
Similartoabstractclass,allinterfacemethodsmustbeimplementedbytheclasswhichis
implementingit.Nooverridekeywordisrequiredwhileimplementinganinterface.Just
likeaninheritance,interfacescan
beimplementedusingsymbolcolon(:).

20. Unit-1Introductionto
ASP.NET
ForExample:
interfaceShape
intarea()://interfacemethod(doesnothaveabody)
classSquare
:Shape
publicintside=4;
publicintarea()
Console.Write("AreaofSquare:");
return(sidesidel;
classProgram
staticvoidMain(stringlargs)
SquaresnewSquaref();
doubleresult=s.area();
Console.Write("10",resut);
MultipleinheritanceisnotsupportedbyC#.Soitcanbeachievedusingimplementing
multipleinterfaces.Todoso,separatethemwithcoma().
ForExample:
interfaceinter1
Voidmethod1(};
interfaceinter2

21. 20 Unit-1IntroductiontoASP.NEI
Voidmethod2(};
classDemoClass:interface1,interface2
publicvoidmethod1()
Console.Writeline("FirstInterfaceMethod");
publicvoidmethod2()
Console.WriteLine("SecondInterfaceMethod.");
classProgram
staticvoidMain(stringllargs)
DemoClassmyObj=newDemoClass();
myObj.method1();
myObj.method2();
1.5.13Polymorphism:
Thepolymorphismistheprocessofusinganoperatororfunctionindifferentwaysfor
differentdatainput.Inotherwords,itistheabilitytoredefinemethodsforderived
classes.
Therearebasicallytwotypeofpolymorphism:
1.Compiletimepolymorphism:Itisachievedbymethodoroperatoroverloading.tisalso
knownasstaticbindingorearlybindingasatcompiletimeonlycompilerknowsthatwhat
typeofobjectitisbindingtoandwhatarethemethoditisgoingtocall.
ForExample:
publicclassShape

22. Unit-1IntroductiontoASP.NET
publicintAreafinta,intb)
returnab;
publicdoubleArealinta,intb,intc)
returna*b*c;
classProgram
staticvoidMain(stringlargs)
ShapesnewShape()
doubleresult=s.Area(4,5);
Console.Write("10}",result);
result=s.Areal4,5,2);
Console.Write("[0}",result);
2.Runtimepolymorphism:Itisachievedbymethodoverriding.Itisalsoknownas
dynamicbindingorlatebinding.Tooverridebaseclassmethods,'virtualkeywordisused
withbaseclassmethodsand'override'keywordisusedwitheachderivedclassmethods
tooverride.
ForExample:
classShape
publicvirtualvoidarea()
Console.write("InShapeclassmethod");

23. 22
Unit-1IntroductiontoASP.NET
classCircle:Shape
publicoverridevoidarea()
Console.Write("InCircleclassmethod");
classTriangle:Shape
publicoverridevoidarea(
Console.Write("lnTriagleclassmethod");
classProgram
staticvoidMain(stringllargs)
Shapesh=newShape(
sh.area();
CirclecnewCirclel);
C.area();
Trianglet
newTriangle();
t.area()
1.6EventDrivenProgramming:
Whensomethingspecifichasoccurredinsignificanceforsystemhardwareorsoftwareis
callanEvent.Inotherwords,Eventisanotificationthatsomethinghasoccurredand
detectedbytheprogram.Asegmentofcodethatisexecutedinresponsetoaneventis
calledaneventhandler.

24. Unit-1IntroductiontoASP.NET
23
Aneventdrivenprogrammingisaprogrammingapproachinwhichtheflowofthe
programisdeterminedbyaneventlikebuttonclicked,textchangeetc.Thatmeansit
enablesyoutowritecodethatwillexecuteinresponsetoeventsraisedbyparticularuser
action.
ASP.NETworkslikeasfollow:
1.Whenfirsttimepageisexecuted,itwillcreatethepageandthecontrolobjects
alongwiththecodeinitializationisexecutedandpageisprovided.
2.Anyeventcanbetriggeredassomeactionisperformedbytheeuserwhenthe
pageisserved.
3.
IfanyeventgeneratesthepostbackoftheformthanASP.NETrepondsthepage
byrecreatingit.
4Thenitwillraisestheappropriateeventwhichhastriggeredthepostback.
5.Last,modifiedpageisprovidedtoHTMLandservedtotheclient.
1.6.1PageLifeCycle:
WheneveryourequestanASP.NETpage,aparticularsetofeventsisraisedinparticular
sequence.Thissequenceofeventsiscalledthepageexecutionlifecycle.
Code
Behind
Clas
NET Generate
EngineParse
Reques
spx
Generate
Compile
PageClass
Request
2dRequest
nstantiation
nstantiate,
ProcessandResponse
PageClass Provide
Figure7:PageLifeCycle
Whentherequestcomesfromthe.aspxpage,itisgivenforparsingtoasp.netengine.
Thenacombinedpageclassisgeneratedfromthatparsedpageandthecodebehindclass
andthenitiscompiled.Atlast,theinstanceoftheclassiscreatedandprovidedtothe
user.

25. 24
Unit-1IntroductiontoASP.NET
1.6.1.1PageLifeCycleStages:
i.PageRequest
Thisiswhenthepageisfirstrequestedfromtheserver.Whenthepageisrequested,
theserverchecksifitisrequestedforthefirsttime.
Ifso,thenitneedstocompile
thepage,parsetheresponseandsenditacrosstotheuser.Ifitisnotthefirsttime
thepageisrequested,thecacheischeckedtoseeifthepageoutputexists.
Ifso,
thatresponseissenttotheuser.
ii.Start
Inthisphase,2objects,knownastheRequestandResponseobjectareset.
Ifthe
requestisanoldrequestorpostback,theIsPostBackpropertyofthepageissetto
true.TheUICulturepropertyofthepageisalsoset.
ilil.PageInitialization
Inthisphase,controlsonthepageareavailableandeachcontrol'sUniquelD
propertyisset.Amasterpageandthemesarealsoappliedtothepageifapplicable.
Ifthecurrentrequestisapostback,thepostbackdatahasnotbeenloadedand
controlpropertyvalueshavenotbeenrestoredtothevaluesfromviewstate.
iv.Load
Duringthisphase,ifthecurrentrequestisapostback,controlpropertiesaresetto
utilizetheviewstateandcontrolstatevalueslikeifatextboxissupposedtohavea
defaultvalue,thatvalueisloadedduringthepageloadtime.
v.Validation
Inthisphase,whenthevalidationcontrolsarepresentonthepage,thanonits
successfulexecution,IsValidpropertyofthepageissettotrue.
vi.PosthackEventHandling
Inthisphase,controleventhandlersarecalled
iftherequestisapostback.That
meansthiseventistriggeredifthesamepageisbeingloadedagain.Thishappensin
responsetoanearlierevent.Sometimestherecanbeasituationthatauserclickson
asubmitbuttononthepage.Inthiscase,
thesamepageisdisplayedagain.Insucha
case,thePostbackeventhandleriscalled.
vii.Rendering

26. Unit-1Introductionto
ASP.NET
Beforethisphase,viewstateissavedforthepageandallcontrols.Duringthisstage,
thepagecallstheRender()methodforeachcontrolandwritesitsoutputtothe
OutputStreamobjectofthepage'sResponseproperty.
vili.Unload
Theunloadmethodtakesafterthepageisfullyloadedandisreadytoterminate.At
thispoint,renderedpageissenttotheclientandpagepropertiessuchasResponse
andRequestareunloadedandclean-upisdone.
1.6.1.2PageEvents:
Followingisthesequenceofeventsraisedwheneveryourequestapage:
i.Prelnit
Itisthefirsteventinthepagelifecycle.ItcheckstheIsPostbackpropertyand
determineswhetherthepageisapostback.Thisistheonlyeventwhereprogrammatic
accesstomasterpagesandthemesisallowed.Youcandynamicallysetthevaluesof
masterpagesandthemesinthisevent.Youcanalsocreatecontrolsdynamicallyinthis
event.
.
Init
Thiseventfiresaftereachcontrolhasbeeninitialized,eachcontrol'sUniqueIDisset.You
canusethiseventtoreadandinitializevalueforthecontrols.Thiseventisfiredfirstfor
thebottom-mostcontrolinthehierarchy,andthenfiredupthehierarchyuntilitisfired
forthepageitself.
ii.InitComplete
Thiseventallowstrackingofviewstate.Allthecontrolsturnonview-statetracking
iv.PreLoad
ThePreLoadeventisusedforperformingthepageprocessingonthepagebeforethe
controlisloaded.Wecanprocessanykindofoperationthatneedstoperformbefore
pageload.
v.Load
Thisisthefirstplaceinthepagelifecyclethatallvaluesarerestored.ThePageobjectcalls
theOnLoadmethodandthenrecursivelydoesthesameforeachchildcontroluntilthe
pageandallcontrolsareloaded.TheLoadeventofindividualcontrolsoccursafterthe

27. 26 Unit-1IntroductiontoASP.NET
Loadeventofthepage.Thiseventisusetosetthepropertiesofthecontrolsanditcan
alsobeusedtoestablishdatabaseconnection.
vi.ControlEvents
Theseeventsareusedtohandlespecificcontrolevents,suchasaButtoncontrol'sClick
event.
vii.PreRender
Thiseventoccursjustbeforetheoutputisprovided.Byhandlingthisevent,pagesand
controlscanperformanyupdatesbeforetheoutputisprovided.
vii.PreRenderComplete
AsthePreRendereventisrecursivelyfiredforallchildcontrols,thiseventensuresthe
completionofthepre-renderingphase.
ix.SaveStateComplete
Inthisevent,stateofcontrolonthepageissaved.Personalization,controlstateandview
stateinformationissaved.
x.Unload
Thisisthelastphaseofthepagelifecycle.ItraisestheUnLoadeventforallthecontrols
recursivelyandforthepageitself.Itisusefulforfinalcleanupsuchasclosingdatabase
connectionoranyotherrequestedspecifictasks.

28. Unit-1IntroductiontoASP.NET
27
Questions:
Q-1.Explain.NETFramework2.0
Q-2.WhatisCompileCode?Listoutitsbenefits.
Q-3.WhatisthedifferencebetweenCodeBehindandInlineCoding?
Q-4.ExplainCLRindetail.
Q-5.ExplainObjectOrientedConcepts.
Q.6ExplainASP.NETPageLifeCycle.