Where and how is the _ViewStart.cshtml layout file linked?

Question

Here\'s the About.cshtml from the default MVC 3 template:

@{
    ViewBag.Title = \"About Us\";
}

About

     Put content here.         


        

Answer 1

The source code is a much better place to look for this than the documentation.

Referencing the MVC 6 code from Github, we have a few files of interest

----update----

Due to source structure changes, the information on how viewstart pages are gathered can now be found in RazorViewEngine.cs look for "GetViewStartPages" function.

----/update----

To answer how they come into play, look at RazorView, Which I believe (because of IView) is tied in to the MVC pipeline. This file has a RenderAsync method that gets called from the MVC pipeline to render the requested view.

RenderAsync makes calls to RenderPage AND THEN RenderLayout (NOTE THE ORDER). The RenderPage first makes calls to deal with viewstart files (note plural, there could be more than one _viewstart file).

So, the information you seek can be obtained from RenderViewStartAsync function in RazorView.cs file under Microsoft.AspNet.Mvc.Razor namespace.