MVVM is stand for model-view viewmodel in which the Glue code treated as View Model which is basically focuses on separation of concerns to make the implementation of an application structure a lot more simpler to create as well as maintain. The MVVM work as an interface between Model and View. MVVM is also provide data binding between View and Model data and it is also handles all the UI (User Interference) actions by using command. In View we can binds its control value to properties on a ViewModel which in turn, exposes data contained in Model objects. The MVVM have three keys patterns : 1. Model for Business rule, data access, model classes. 2. View is User interface (XAML). 3. ViewModel for Agent or middle man between view and model.