title: Azure Function in C# on v2 - How to access the portal Application Settings
body: <p>As of September 2019 coding an Azure Function in C# has some crossover with ASP.NET Core, especially around dependency injection.</p>
  
  <p>Does the hidden "host builder" read the runtime Application Settings - which I think are actually just environment variables at runtime - into the configuration system, <code>IConfiguration</code>?</p>
  
  <p>Thus, double underscore names can be used to recreate the hierarchical config we C# devs know.</p>