Class Library cannot be started directly

September 7, 2016

In Visual Studio 2015, I created a ASP.NET Web Application project, and then chose the Empty template.

When you try and run this, you'll probably get the following error:

A project with an Output Type of Class Library cannot be started directly.
In order to debug this project, add an executable project to this solution which references to the library project. 
Set the executable project as the startup project

In order to get around this, right click the project and choose Set as StartUp Project.