在Dotnet Core 2.0中，启动构造函数只需要一个iconfigure -parameter。

    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;
    }

如何了解那里的托管环境? 我将它存储在ConfigureAppConfiguration期间的Program-class中 (使用完整的BuildWebHost而不是WebHost.CreateDefaultBuilder):

public class Program
{
    public static IHostingEnvironment HostingEnvironment { get; set; }

    public static void Main(string[] args)
    {
        // Build web host
        var host = BuildWebHost(args);

        host.Run();
    }

    public static IWebHost BuildWebHost(string[] args)
    {
        return new WebHostBuilder()
            .UseConfiguration(new ConfigurationBuilder()
                .SetBasePath(Directory.GetCurrentDirectory())
                .AddJsonFile("hosting.json", optional: true)
                .Build()
            )
            .UseKestrel()
            .UseContentRoot(Directory.GetCurrentDirectory())
            .ConfigureAppConfiguration((hostingContext, config) =>
            {
                var env = hostingContext.HostingEnvironment;

                // Assigning the environment for use in ConfigureServices
                HostingEnvironment = env; // <---

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

                if (env.IsDevelopment())
                {
                    var appAssembly = Assembly.Load(new AssemblyName(env.ApplicationName));
                    if (appAssembly != null)
                    {
                        config.AddUserSecrets(appAssembly, optional: true);
                    }
                }

                config.AddEnvironmentVariables();

                if (args != null)
                {
                    config.AddCommandLine(args);
                }
            })
            .ConfigureLogging((hostingContext, builder) =>
            {
                builder.AddConfiguration(hostingContext.Configuration.GetSection("Logging"));
                builder.AddConsole();
                builder.AddDebug();
            })
            .UseIISIntegration()
            .UseDefaultServiceProvider((context, options) =>
            {
                options.ValidateScopes = context.HostingEnvironment.IsDevelopment();
            })
            .UseStartup<Startup>()
            .Build();
    }

Ant然后像这样在ConfigureServices中读取它:

public IServiceProvider ConfigureServices(IServiceCollection services)
{
    var isDevelopment = Program.HostingEnvironment.IsDevelopment();
}

你可以很容易地在ConfigureServices中访问它，只是在Startup方法期间将它持久化到一个属性，该方法首先被调用并将其传递进来，然后你可以从ConfigureServices访问该属性。

public Startup(IWebHostEnvironment env, IApplicationEnvironment appEnv)
{
    ...your code here...
    CurrentEnvironment = env;
}

private IWebHostEnvironment CurrentEnvironment{ get; set; } 
 
public void ConfigureServices(IServiceCollection services)
{
    string envName = CurrentEnvironment.EnvironmentName;
    ... your code here...
}

如果你需要在你的代码库中某个不容易访问IHostingEnvironment的地方测试这个，另一个简单的方法是这样做的:

bool isDevelopment = Environment.GetEnvironmentVariable("ASPNETCORE_ENVIRONMENT") == "Development";

在Dotnet Core 2.0中，启动构造函数只需要一个iconfigure -parameter。

    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;
    }

如何了解那里的托管环境? 我将它存储在ConfigureAppConfiguration期间的Program-class中 (使用完整的BuildWebHost而不是WebHost.CreateDefaultBuilder):

public class Program
{
    public static IHostingEnvironment HostingEnvironment { get; set; }

    public static void Main(string[] args)
    {
        // Build web host
        var host = BuildWebHost(args);

        host.Run();
    }

    public static IWebHost BuildWebHost(string[] args)
    {
        return new WebHostBuilder()
            .UseConfiguration(new ConfigurationBuilder()
                .SetBasePath(Directory.GetCurrentDirectory())
                .AddJsonFile("hosting.json", optional: true)
                .Build()
            )
            .UseKestrel()
            .UseContentRoot(Directory.GetCurrentDirectory())
            .ConfigureAppConfiguration((hostingContext, config) =>
            {
                var env = hostingContext.HostingEnvironment;

                // Assigning the environment for use in ConfigureServices
                HostingEnvironment = env; // <---

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

                if (env.IsDevelopment())
                {
                    var appAssembly = Assembly.Load(new AssemblyName(env.ApplicationName));
                    if (appAssembly != null)
                    {
                        config.AddUserSecrets(appAssembly, optional: true);
                    }
                }

                config.AddEnvironmentVariables();

                if (args != null)
                {
                    config.AddCommandLine(args);
                }
            })
            .ConfigureLogging((hostingContext, builder) =>
            {
                builder.AddConfiguration(hostingContext.Configuration.GetSection("Logging"));
                builder.AddConsole();
                builder.AddDebug();
            })
            .UseIISIntegration()
            .UseDefaultServiceProvider((context, options) =>
            {
                options.ValidateScopes = context.HostingEnvironment.IsDevelopment();
            })
            .UseStartup<Startup>()
            .Build();
    }

Ant然后像这样在ConfigureServices中读取它:

public IServiceProvider ConfigureServices(IServiceCollection services)
{
    var isDevelopment = Program.HostingEnvironment.IsDevelopment();
}

在NET6中，启动和程序合并为一个文件，启动中不再有ConfigureServices方法。现在你可以简单地使用

builder.Environment.IsProduction() 
builder.Environment.IsStaging()
builder.Environment.IsDevelopment()

就在第一行之后

var builder = WebApplication.CreateBuilder(args);

这可以在没有任何额外属性或方法参数的情况下完成，如下所示:

public void ConfigureServices(IServiceCollection services)
{
    IServiceProvider serviceProvider = services.BuildServiceProvider();
    IHostingEnvironment env = serviceProvider.GetService<IHostingEnvironment>();

    if (env.IsProduction()) DoSomethingDifferentHere();
}