Model-View-ViewModel Pattern

Introduction

In conventional user interface programming techniques (as we know it from WinForms) we usually add event handlers to controls and implement the logic of a view in the code-behind. It is the most simple and fastest way to get a functional user interface. But this approach has some disadvantages:

• Presentation and logic are tightly coupled
• Replacing a control on the view often requires code changes
• You cannot have more than one view sharing the same logic
• To test the user interface logic you need to do complex UI testing.

Introducing the Model-View-ViewModel pattern

WPF brings up a very flexible and powerful databinding framework and this favors a new pattern how to bind presentation and logic together.

The idea of the MVVM pattern is the following:

• A model that contains the data
• A passive view-model that collects and prepares the data so that is can easy be consumed by the view.
• And a view that is defined in XAML and should not have any logic in the code-behind. It binds to the view-model by only using data binding.

Model-View-ViewModel Example

Model

ViewModel

View

 Comments on this article

Divyadhar Ojha	Commented on 14.May 2010 It's Not Enough For Code .
James	Commented on 26.May 2010 Explainations are not good enough to understand more
Vinay	Commented on 1.June 2010 I could very well understand what you mentioned in this article till now. Eagerly waiting for you to finish it to understand it further..
Vaishno	Commented on 11.June 2010 hi can you please provide some more details including sample that implements that .
Tauqir	Commented on 15.June 2010 Please can you add some update on the topic, it will be really thankfull.
D	Commented on 29.June 2010 your article is perfect to understand and is needed more better. Also Lol'd is big douche.
Poorna	Commented on 1.July 2010 Guys...Please dont complain about this postings, at least he is trying to contribute to dev community.
Tom	Commented on 8.July 2010 http://msdn.microsoft.com/en-us/magazine/dd419663.aspx
always_compl...	Commented on 21.July 2010 Why post it if it is not complete?? Thanks for your other articles though.
john	Commented on 27.July 2010 I don't know about you guys, but this link goes inside my bookmarks. This what I searched for some time. A quick review of different technologies and features like xaml, wpf, mvvm etc. It's kind of like a reminder of all technologies in one bucket. Good job!
theDude	Commented on 2.August 2010 That is a seriously gay photo of your boyfriend on the header.
theDude	Commented on 2.August 2010 Actually the gay tard in the header probably has a gerbal up his butt. Which explains the gay grin on his face.
theDude	Commented on 2.August 2010 So back to the gay photo on the header... Did his mom dress him or did he just buy whatever was on the first display mannequin at GAP? I love irony.
theDude	Commented on 2.August 2010 Ok, so I got it now. The sun rising over the mountian in the header is a metaphore for the gay dude coming out the closet to the right.
theDude	Commented on 2.August 2010 To the gay dude in the header: referee shirts have the stripes running vertically not horizontally. get it together..
theDude	Commented on 2.August 2010 So I bet if we could scroll the header down you'd see the gay dude's pants down and his boyfriend going to town on his cock. mmmm, gay
corvette	Commented on 5.August 2010 Chris, Please can you delete theDude's pathetic and immature comments. PS Please can you answer how MVVM differs from MVC. I can probably find the info elsewhere I know (eg http://stackoverflow.com/questions/667781/what-is-the-difference-between-mvc-and-mvvm), but why would I do that when your explanations are usually so good ? Cheers PS If I were you I would only allow comments from registered users. Shame but how else can you deal with Sad people.
Darshit Dave	Commented on 11.August 2010 Hi Chris, I started to use this site a day before and enjoying learning WPF very qucikly. I had heard about VVMM MVVM pattern and really eager to learn it. Can you please complete the architecture when ever you get time? I know its hard to find out time from routine work, but we do expect your valuable guidance. Thanks.
Jimsom	Commented on 13.August 2010 look forward completion
venkadesh	Commented on 17.August 2010 Let me send the samples
john	Commented on 18.August 2010 @theDude are you gay dude ?
theDude	Commented on 19.August 2010 @john, how long have you and the fag in the header been dating? Which of your mom's dress you two?
theDude	Commented on 21.August 2010 Sounds like this article is really a metaphore for the Ass-Poke-PokeAss pattern. According to the diagram when you get to the Ass, you recieve double penetration.
theDude	Commented on 25.August 2010 Speaking of double penetration, hows the faggot in the header holding up these days?
shankar	Commented on 31.August 2010 wats the use of mvvm?