https://github.com/vmandic/custom-iconfiguration-startup-injection

This is a sample #dotnetcore project demonstrating on how to modify the IConfiguration injected in generic host Startup.cs CTOR.
https://github.com/vmandic/custom-iconfiguration-startup-injection

configuration csharp dependency-injection dotnet dotnetcore webapi webapp

Last synced: 2 months ago
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This is a sample #dotnetcore project demonstrating on how to modify the IConfiguration injected in generic host Startup.cs CTOR.

• Host: GitHub
• URL: https://github.com/vmandic/custom-iconfiguration-startup-injection
• Owner: vmandic
• Created: 2020-12-26T23:21:30.000Z (over 5 years ago)
• Default Branch: main
• Last Pushed: 2020-12-26T23:25:37.000Z (over 5 years ago)
• Last Synced: 2025-10-30T22:36:56.475Z (8 months ago)
• Topics: configuration, csharp, dependency-injection, dotnet, dotnetcore, webapi, webapp
• Language: C#
• Homepage:
• Size: 8.79 KB
• Stars: 1
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

          
# How to modify the IConfiguration injected into Startup constructor

This is a sample #dotnetcore project demonstrating on how to modify the IConfiguration injected in generic host Startup.cs CTOR.

The core thing to do is to call the `ConfigureAppConfiguration` in generic host construction as followed:

```csharp

public class Program

  {

    private static IConfigurationBuilder ConfigurationBuilder;

    public static async Task Main(string[] args)

    {

      ConfigurationBuilder = new ConfigurationBuilder()

        .SetBasePath(Directory.GetCurrentDirectory())

        .AddJsonFile("appsettings.json", optional : false)

        .AddJsonFile($"appsettings.{Environment.GetEnvironmentVariable("ASPNETCORE_ENVIRONMENT")}.json", optional : true)

        .AddJsonFile("appsettings.localhost.json", optional : true)

        .AddEnvironmentVariables();

      await CreateHostBuilder(args).Build().RunAsync();

    }

    public static IHostBuilder CreateHostBuilder(string[] args)

    {

      return Host.CreateDefaultBuilder(args)

        .UseContentRoot(Directory.GetCurrentDirectory())

        .ConfigureAppConfiguration(configBuilder =>

        {

          Console.WriteLine("ConfigureAppConfiguration called...");

          // NOTE: this does not work, we will have to reassign one by one in foreach below

          //configBuilder = ConfigurationBuilder; 

          

          // NOTE: clear existing stack built by CreateDefaultBuilder method

          configBuilder.Sources.Clear();

          foreach (var configSource in ConfigurationBuilder.Sources)

          {

            configBuilder.Add(configSource);

          }

        })

        .ConfigureWebHostDefaults(webBuilder =>

          webBuilder.UseStartup());

    }

  }

```