c# - ASP.Net Core 2.2 读取 appsettings.json

Question

ASP.NetCore 2.2、VisualStudio 2019

我正在尝试弄清楚如何将 web.config 文件转换为 appsettings.json，但我遗漏了一些东西。

我有一个 startup.cs 文件，看起来像(为简洁起见进行了编辑):

using System;
using MyCoolApp.Models.Commodities;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Rewrite;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;

namespace MyCoolApp {
    public class Startup {
        public Startup(IHostingEnvironment env) {
            var builder = new ConfigurationBuilder()
                .SetBasePath(AppDomain.CurrentDomain.BaseDirectory)
                .AddJsonFile("appsettings.json", true, true)
                .AddJsonFile($"appsettings.{env.EnvironmentName}.json", true)
                .AddEnvironmentVariables();

            Configuration = builder.Build();
        }

        private IConfiguration Configuration { get; }

        public void ConfigureServices(IServiceCollection services) {
            services.AddDistributedMemoryCache();

            services.Configure<IISServerOptions>(
                options => { 
                    options.AutomaticAuthentication = false; 
                }
            );

            services.AddMvc().SetCompatibilityVersion(
                CompatibilityVersion.Version_2_2
            );

            var foo = Configuration.GetConnectionString("CommoditiesContext");
            services.AddDbContext<CommoditiesContext>(
                options => options.UseSqlServer(
                    Configuration.GetConnectionString("CommoditiesContext")
                )
            );

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env) {
            ...
        }
    }
}

注意 var foo = Configuration.GetConnectionString(...) 行。

我有一个 web.config 文件，看起来像(经过大量编辑):

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <connectionStrings>
    <add name="CommoditiesContext" connectionString="Server=mydb.company.com;Initial Catalog=Things;Integrated Security=True;providerName=System.Data.SqlClient;" />
  </connectionStrings>
</configuration>

我已经把它变成了“顶级”appsettings.json 文件:

{
    "Logging": {
        "LogLevel": {
            "Default": "Warning"
        }
    },
    "AllowedHosts": "*",
    "connectionStrings": {
        "CommoditiesContext": "Server=mydb.company.com;Initial Catalog=Things;Integrated Security=True;providerName=System.Data.SqlClient;"
    }
}

我有一个 appsettings.Development.json 文件，如下所示:

{
    "Logging": {
        "LogLevel": {
            "Default": "Debug",
            "System": "Information",
            "Microsoft": "Information"
        }
    },
    "location": {
        "path": ".",
        "inheritInChildApplications": "false",
        "system.webServer": {
            "handlers": [],
            "aspNetCore": {
                "processPath": "%LAUNCHER_PATH%",
                "arguments": "%LAUNCHER_ARGS%",
                "stdoutLogEnabled": "true",
                "stdoutLogFile": ".\\logs\\stdout",
                "hostingModel": "InProcess",
                "environmentVariables": [
                    {
                        "name": "ASPNETCORE_HTTPS_PORT",
                        "value": "44375"
                    },
                    {
                        "name": "ASPNETCORE_ENVIRONMENT",
                        "value": "Development"
                    },
                    {
                        "name": "COMPLUS_ForceENC",
                        "value": "1"
                    }
                ],
                "handlerSettings": [
                    {
                        "name": "debugFile",
                        "value": "aspnetcore-debug.log"
                    },
                    {
                        "name": "debugLevel",
                        "value": "FILE,TRACE"
                    }
                ]
            },
            "modules": [],
            "isapiFilters": []
        }
    }
}

我也有一个 `Production one，但让我们暂时限制噪音。

我现在的问题是，当我在本地调试时，我可以在 startup.cs 的 services.AddDbContext 行上设置一个 bp，然后查看值foo。它是 null。我要么错误地构建了 appsettings.json 文件，要么错误地读取了配置信息，但我不知道是哪一个。

我错过了什么？

编辑

program.cs

using Microsoft.AspNetCore;
using Microsoft.AspNetCore.Hosting;

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

        private static IWebHostBuilder CreateWebHostBuilder(string[] args) {
            return WebHost.CreateDefaultBuilder(args)
                .UseIIS()
                .UseStartup<Startup>();
        }
    }
}

Answer 1

问题是您在启动构造函数中为配置设置了错误的基本路径。 AppDomain.CurrentDomain.BaseDirectory 会给你错误的位置，因此不会加载任何配置文件。相反，请考虑改用 System.IO.Directory.GetCurrentDirectory()。