'ConfigurationBuilder' does not contain a definition for 'AddJsonFile'

Question

I have the following error:

Program.cs(15,72): error CS1061: 'ConfigurationBuilder' does not contain a definition for 'AddJsonFile' and no accessible extension method 'AddJsonFile' accepting a first argument of type 'ConfigurationBuilder' could be found (are you missing a using directive or an assembly

The project is a dotnet core app, console application, using Azure Search SDK

The line of error is below:

using System; using System.Linq; using System.Threading; using Microsoft.Azure.Search; using Microsoft.Azure.Search.Models; using Microsoft.Extensions.Configuration; using Microsoft.Spatial;  namespace DemoSearchIndexer {     class Program     {         static void Main(string[] args)         {             IConfigurationBuilder builder = new ConfigurationBuilder().AddJsonFile("appsettings.json");             IConfigurationRoot configuration = builder.Build(); 

Answer 1

The AddJsonFile extension method is available in NuGet:

• Microsoft.Extensions.Configuration.Json

When building an ASP.NET Core application, which usually references Microsoft.AspNetCore.App (or, historically, Microsoft.AspNetCore.All), you get this "for free".

When building a console application, or something that doesn't reference the metapackages, you need an explicit reference to Microsoft.Extensions.Configuration.Json.