.Net Core 3.1 将额外的 config.json 文件添加到 Startup 中的配置参数

Question

I need to add another configuration file to my .Net Core Blazor project. Other sources (such as this ) mention using configuration builder in .Net core 2.2, but since in 3.1 the configuration is passed as a parameter into Startup, I have no way of appending another config onto it as far as I can tell. Maybe I'm looking at it wrong, but I'm assuming that the configuration passed in as a param has important configuration properties, therefor building it my self with just the additional config file seems like it leave those config properties out.

Ex: Doesn't work but should paint a picture of what I'm trying to do.

public Startup(IConfiguration configuration)
{
      Configuration = configuration;
      var builder = new ConfigurationBuilder(configuration)
              .AddJsonFile("accountconstants.json", optional: true, reloadOnChange: true);
      });
}

Answer 1

You can do it in Program.cs ie earlier in the pipeline rather than in Startup.cs .

Example:

public class Program
{
    public static void Main(string[] args)
    {
        CreateHostBuilder(args).Build().Run();
    }

    public static IHostBuilder CreateHostBuilder(string[] args) =>
        Host.CreateDefaultBuilder(args)
            .ConfigureAppConfiguration((hostContext, config) =>
            {
                var env = hostContext.HostingEnvironment;

                config.AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
                    .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true, reloadOnChange: true);
            })
            .ConfigureWebHostDefaults(webBuilder =>
            {
                webBuilder.UseStartup<Startup>();
            });
}

Answer 2

Your approach should work, but needs a little bit of tweaking.

The configuration that you create needs to be added to the DI Container. The documentation for this is here .

I've achieved it as well in Azure Functions and other projects through the following:

public void ConfigureServices(IServiceCollection services)
{
    services.AddSingleton<IConfiguration>(provider => new ConfigurationBuilder()
            .AddEnvironmentVariables()
            .AddJsonFile("accountconstants.json", optional: true, reloadOnChange: true)
            .Build());
}