Build failing on .net Core app due to missing definition

Question

I\'m trying to build my .NET Core app from the CLI using dotnet build, but every single time I get this error:

\'IConfigurationBuilder\' doe

Answer 1

You need the Microsoft.Extensions.Configuration namespace in scope to get that extension method. Either fully qualify it, or add this to the top of your file:

using Microsoft.Extensions.Configuration;

You also will need the NuGet reference Microsoft.Extensions.Configuration.EnvironmentVariables.