Views/UI Rendering in MVC

Views in MVC

The ASP.NET MVC framework supports the use of a view engine(Razor/ASPX) to generate views (UI). 

The Views folder stores the files (HTML files) related to the display of the application (the user interfaces). These files may have the extensions html, asp, aspx, cshtml, and vbhtml, depending on the language content.The Views folder contains one folder for each controller.

In the Model-View-Controller (MVC) pattern, views are intended exclusively for encapsulating presentation logic. They should not contain any application logic or database retrieval code. All application logic should be handled by the controller. A view renders the appropriate UI by using the data that is passed to it from the controller. This data is passed to a view from a controller action method by using the View method.

A view page is an instance of the ViewPage class. It inherits from the Page class and implements the IViewDataContainer interface. The ViewPage class defines a ViewDataproperty that returns a ViewDataDictionary object. This property contains the data that the view should display.

The MVC framework uses URL routing to determine which controller action to invoke, and the controller action then decides which views to render.

Partial Views

A partial view enables you to define a view that will be rendered inside a parent view. Partial views are implemented as ASP.NET user controls (.ascx).

When a partial view is instantiated, it gets its own copy of the ViewDataDictionary object that is available to the parent view. The partial view therefore has access to the data of the parent view. However, if the partial view updates the data, those updates affect only the partial view's ViewData object. The parent view's data is not changed.

The ASP.NET MVC framework includes helper methods that provide an easy way to render HTML in a view. This topic explains how to work with the most frequently used HTML helper.

To render a view, you call the View method of the controller. To pass data to the view, you use the ViewData property of the ViewPage class. This property returns aViewDataDictionary object that has case-insensitive string keys.