I don’t know about ASP.Net at all, I right click on the file Index.cshtml in views and accidentally choose “Set As Start Page”
Now when I run the application (Ctrl+F5), the error occurs
Server Error in '/' Application.
The resource cannot be found.
Description: HTTP 404. The resource you are looking for (or one of its dependencies) could have been removed, had its name changed, or is temporarily unavailable. Please review the following URL and make sure that it is spelled correctly.
Requested URL: /Views/Home/Index.cshtml
You can change the settings in the Project properties, this other stack article should help: Visual Studio ASP.Net MVC undo set as start page action