Why so many instances of ASP.NET Development Server?

Question

I am debugging a large web application solution, with the main web application project as a single startup project, configured to use IIS for debugging. Whenever I run this application inside Visual Studio 2010, I still get multiple instances (sometimes over 15) of the ASP.NET Development Server starting up as well. Why does this occur?

Answer 1

Visual Studio has a setting in every Web Project's properties by default to start the development server when you are debugging. This enables, for example, a web project which contains Web Services to be available when you've selected a client web site or application to start.

If you do not want this behaviour follow these steps:

1. Select the web project
2. Open the "Properties" window by pressing F4
3. Change the Always Start When Debugging value to False
4. Repeat steps 1-3 for any other web projects in your solution

Source: '"Always Start When Debugging" – Preventing multiple Visual Studio Development Servers from starting' by by Kevin Rintoul

Answer 2

A simple solution if you have many web projects in the same solution: from the Package Manager console:

get-project -all | %{ $_.Properties | ?{ $_.Name -eq "WebApplication.StartWebServerOnDebug" } | %{ $_.Value = $False} }

This will change all web projects Always Start When Debugging setting to false with a single command.