Introduction

1. View (UI)
2. Model (Data displayed in UI)
3. Glue code (Event handling, binding, business logic)

MVP & MVC

MVC Steps

MVVM (Model View ViewModel)

1. Model (Business rule, data access, model classes)
2. View (User interface (XAML))
3. ViewModel (Agent or middle man between view and model)

• ViewModel acts as an interface between model and View.
• ViewModel provides data binding between View and model data.
• ViewModel handles all UI actions by using command.

<TextBlock Text="{Binding Name}"/> 

public string Name
        {
            get
            {
                return this.name;
            }
            set
            {
                this.name = value;
                this.OnPropertyChanged("Name");
            }
        }

public IViewModel Model
        {
            get
            {
                return this.DataContext as IViewModel;
            }
            set
            {
                this.DataContext = value;
            }
        }

Where to Use What in the .NET World

• Model-View-Controller (MVC) pattern
  • ASP.NET MVC 4 Link
  • Disconnected Web Based Applications
• Model-View-Presenter (MVP) pattern
  • Web Forms/SharePoint, Windows Forms
• Model-View-ViewModel (MVVM) pattern
• Silverlight, WPF Link
• Data binding

• Encapsulation is one of the fundamental principles of object-oriented programming.
• Encapsulation is a process of hiding all the internal details of an object from the outside world
• Encapsulation is the ability to hide its data and methods from outside the world and only expose data and methods that are required
• Encapsulation is a protective barrier that prevents the code and data being randomly accessed by other code or by outside the class
• Encapsulation gives us maintainability, flexibility and extensibility to our code.
• Encapsulation makes implementation inaccessible to other parts of the program and protect from whatever actions might be taken outside the function or class.
• Encapsulation provides a way to protect data from accidental corruption
• Encapsulation hides information within an object
• Encapsulation is the technique or process of making the fields in a class private and providing access to the fields using public methods
• Encapsulation gives you the ability to validate the values before the object user change or obtain the value
• Encapsulation allows us to create a "black box" and protects an objects internal state from corruption by its clients.

Separation of logic and presentation

• Having event handlers in the code-behind is bad for testing, since you cannot mock away the view.
• Changing the design of the view often also requires changes in the code, since every element has it's different event handlers.
• The logic is tightly bound to the view. It's not possible to reuse the logic in an other view

• The view-model can easily be tested by using standard unit-tests (instead of UI-testing)
• The view can be redesigned without changing the viewmodel, because the interface stays the same.
• The view-model can even be reused, in sone special cases (this is usually not recommended)

What's the difference between MVVM, MVP and MVC?

MVC - Model-View-Controller

MVP - Model-View-Presenter

MVVM - Model-View-ViewModel