从控制台应用程序中的另一个类调用 appsettings.json 数据

Question

以下是Microsoft 文档中的示例代码，显示了如何在控制台应用程序中使用 appsettings.json：

using System;
using System.Threading.Tasks;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Hosting;

namespace ConsoleJson.Example
{
    class Program
    {
        static async Task Main(string[] args)
        {
            using IHost host = CreateHostBuilder(args).Build();

            // Application code should start here.

            await host.RunAsync();
        }

        static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .ConfigureAppConfiguration((hostingContext, configuration) =>
                {
                    configuration.Sources.Clear();

                    IHostEnvironment env = hostingContext.HostingEnvironment;

                    configuration
                        .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
                        .AddJsonFile($"appsettings.{env.EnvironmentName}.json", true, true);

                    IConfigurationRoot configurationRoot = configuration.Build();

                    TransientFaultHandlingOptions options = new();
                    configurationRoot.GetSection(nameof(TransientFaultHandlingOptions))
                                     .Bind(options);

                    Console.WriteLine($"TransientFaultHandlingOptions.Enabled={options.Enabled}");
                    Console.WriteLine($"TransientFaultHandlingOptions.AutoRetryDelay={options.AutoRetryDelay}");
                });
    }
}

我需要在另一个类的方法中获取配置值，如下所示。我想我会需要使用依赖注入，并发送IConfigurationRoot至myClass如图这个链接，但无法弄清楚到底如何？

using System;
using System.Threading.Tasks;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Hosting;

namespace ConsoleJson.Example
{
    class Program
    {
        static void Main(string[] args)
        {
            using IHost host = CreateHostBuilder(args).Build();

            IDatabase db = xyz.GetDatabase();

            ConfigureServices.Initialize(db);
        }

        static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .ConfigureAppConfiguration((hostingContext, configuration) =>
                {
                    configuration.Sources.Clear();

                    IHostEnvironment env = hostingContext.HostingEnvironment;

                    configuration
                        .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
                        .AddJsonFile($"appsettings.{env.EnvironmentName}.json", true, true);

                    IConfigurationRoot configurationRoot = configuration.Build();

                    TransientFaultHandlingOptions options = new();
                    configurationRoot.GetSection(nameof(TransientFaultHandlingOptions))
                                     .Bind(options);

                    
                });
    }

    class ConfigureServices
    {   public static void Initialize(IDatabase db)
        {
             Console.WriteLine($"TransientFaultHandlingOptions.Enabled={options.Enabled}");
             Console.WriteLine($"TransientFaultHandlingOptions.AutoRetryDelay={options.AutoRetryDelay}");

        }
    }
}

因此，我需要从中获取值appsettings.json并在我的 Initialize 方法中使用它们。我可以通过对值进行硬编码来使用其余的代码。

我尝试在 ConfigureAppConfiguration 之后添加以下行，但无法识别 configurationRoot

.ConfigureServices((_, services) =>services.AddSingleton<IConfigurationRoot>(configurationRoot));

真诚地感谢所有帮助。谢谢

Answer 1

我也有类似的情况。我想将 AppSettings.Json 自定义键访问到我的 asp.net core mvc 项目的控制器中。我正在分享控制台应用程序示例代码，可能对您有帮助。

我使用了标准 VS 2019 控制台应用程序模板和 asp.net core，目标为 .net 5.0。

如何将 AppSettings.Json（特定）键值读取到 C# 控制台应用程序中。

我的项目文件：

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net5.0</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.EntityFrameworkCore" Version="5.0.6" />
    <PackageReference Include="Microsoft.Extensions.Hosting" Version="5.0.0" />
    <PackageReference Include="Microsoft.Extensions.Hosting.Abstractions" Version="5.0.0" />
    <PackageReference Include="Serilog" Version="2.10.0" />
    <PackageReference Include="Serilog.AspNetCore" Version="4.1.0" />
    <PackageReference Include="Serilog.Sinks.MSSqlServer" Version="5.6.0" />
  </ItemGroup>

  <ItemGroup>
    <None Update="appsettings.json">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
    </None>
  </ItemGroup>

</Project>

我的 AppSettings.Json 是：

  {
  "AppSettings": {

    "FTPLocation": "\\\\FTPHostname\\\\c$\\\\Folder\\\\ftpSite\\\\Prod\\",
    "FTPUri": "ftp://ftphostname/myFolder/",
    "CSVFileName": "TestData.csv",
    },
  "ConnectionStrings": {
    "AppDbConnString": "Server=sqlserverhost.domain.com;Database=DBName; Trusted_Connection=True; MultipleActiveResultSets=true"
    ,
"IdentityConnection": "Server=hostname.domain.com;Database=IdentityDBName; Trusted_Connection=True; MultipleActiveResultSets=true"
      },  
    "EmailAddresses": [
          "email1@test.com",
          "email2@test.com",
          "email3@test.com"
        ],  
      "Logging": {
        "LogLevel": {
          "Default": "Warning"
        }
      }
 }

我的 Program.cs 是：

using System;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.DependencyInjection;
using Serilog;
using Microsoft.Extensions.Logging;
using System.IO;

namespace AppSettingsExample
{
    class Program
    {
        public static IConfigurationRoot configuration;
        static void Main(string[] args)
        {
            ServiceCollection serviceDescriptors = new ServiceCollection();

            ConfigureServices(serviceDescriptors);

            Serilog.Log.Information("Building service provider");

            IServiceProvider serviceProvider = serviceDescriptors.BuildServiceProvider();

            Console.WriteLine(configuration.GetConnectionString("AppDbConnString"));

            try
            {
                Serilog.Log.Information("start service provider");
                _ = serviceProvider.GetService<App>().Run();
                Serilog.Log.Information("end service provider");
            }
            catch (Exception ex)
            {
                Serilog.Log.Fatal(ex, "Error in building service ");
                throw;
            }
            finally
            {
                Serilog.Log.CloseAndFlush();
            }

            var connectionString = configuration.GetSection("ConnectionStrings:AppDbConnString").Value;

            Console.WriteLine(connectionString);

            var securityGroups = configuration.GetSection("ADSecurityGroups:SupervisorSecurityGroups").Value.Split(';');

            foreach (var securityGroup in securityGroups)
            {
                Console.WriteLine(securityGroup);
            }
        }
        private static void ConfigureServices(IServiceCollection serviceCollection)
        {
            serviceCollection.AddSingleton(LoggerFactory.Create(builder =>
            {
                builder.AddSerilog(dispose: true);
            }));

            serviceCollection.AddLogging();

            configuration = new ConfigurationBuilder()
                .SetBasePath(Directory.GetParent(AppContext.BaseDirectory).FullName)
                .AddJsonFile("appsettings.json")
                .Build();

            serviceCollection.AddSingleton<IConfigurationRoot>(configuration);

            serviceCollection.AddTransient<App>();

        }


    }
}

我的 App.cs 是：

using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Logging;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace AppSettingsExample
{
    public class App
    {
        private readonly IConfigurationRoot _config;
        private readonly ILogger<App> _logger;

        public App(IConfigurationRoot config, ILoggerFactory loggerFactory)
        {
            _logger = loggerFactory.CreateLogger<App>();
            _config = config;
        }

        public async Task Run()
        {
            List<string> emailAddresses = _config.GetSection("EmailAddresses").Get<List<string>>();
            foreach (string emailAddress in emailAddresses)
            {

                Console.WriteLine(emailAddress);
            }
        }
    }
}

该控制台应用程序的输出：