TheModelViewControllerFramework

JogeshK.Muppala

DesignPatterns• Well-documentedsolutiontoarecurringproblem– Alsoreferredtoasanarchitecturalpattern

• Softwaredesignpattern– Reusablesolutiontocommonlyoccurringproblems– Gangoffour:E.Gammaetal.DesignPatterns:ElementsofReusableObject-OrientedSoftware,Addison-Wesley,1994

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https://en.wikipedia.org/wiki/Software_design_pattern

TheModel-View-Controller(MVC)Framework

• Softwareengineeringarchitecturepattern– Isolationofdomainlogic

fromuserinterface– Permitsindependent

development,testingandmaintenance(separationofconcerns)

http://en.wikipedia.org/wiki/Model–View–Controller

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Controller

View Model

MVCFramework• Model

– managesthebehavioranddataoftheapplicationdomain

– respondstorequestsforinformationaboutitsstate(usuallyfromtheview)

– respondstoinstructionstochangestate(usuallyfromthecontroller)

– Inevent-drivensystems,themodelnotifiesobservers(usuallyviews)whentheinformationchangessothattheycanreact

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Controller

View Model

MVCFramework• View

– rendersthemodelintoaformsuitableforinteraction,typicallyauserinterfaceelement

– Multipleviewscanexistforasinglemodelfordifferentpurposes

– Aviewporttypicallyhasaonetoonecorrespondencewithadisplaysurfaceandknowshowtorendertoit

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Controller

View Model

MVCFramework• Controller– receivesuserinputandinitiatesaresponsebymakingcallsonmodelobjects

– Acontrolleracceptsinputfromtheuserandinstructsthemodelandviewporttoperformactionsbasedonthatinput

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Controller

View Model

ModelViewView-Model(MVVM)

• DescendentofMVC• SometimescalledModel-

View-Binder• Viewmodel

– Abstractionoftheviewthatexposespublicpropertiesandcommands

– Declarativedatabinding

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View ViewModel Model

DataBinding

PresentationandPresentationLogic

BusinessLogicandData