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";

从ASP开始。NET Core 3.0中，从ConfigureServices和Configure中访问环境变量要简单得多。

只需将IWebHostEnvironment注入到启动构造函数本身。像这样…

public class Startup
{
    public Startup(IConfiguration configuration, IWebHostEnvironment env)
    {
        Configuration = configuration;
        _env = env;
    }

    public IConfiguration Configuration { get; }
    private readonly IWebHostEnvironment _env;

    public void ConfigureServices(IServiceCollection services)
    {
        if (_env.IsDevelopment())
        {
            //development
        }
    }

    public void Configure(IApplicationBuilder app)
    {
        if (_env.IsDevelopment())
        {
            //development
        }
    }
}

参考:https://learn.microsoft.com/en - us/aspnet/core/fundamentals/environments?view=aspnetcore - 3.0 # inject-iwebhostenvironment-into-the-startup-class

对于blazor服务器应用程序，我这样做:Startup.cs直接在命名空间声明add

namespace myProjectName.Server

public static class myGlobals

{
    public static bool isDevelopment = true;
}

Startup.cs找到Configure方法和env. cs的现有检查。并将上面声明的静态IsDevelopment设置为true或false。

    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        if (env.IsDevelopment())
        {
           myGlobals.isDevelopment = true;
        }
        else false

在ApplicationUser中初始化数据库连接或其他任何地方

        if (myGlobals.isDevelopment)
        {

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();
}

来自文档

Configure和ConfigureServices支持特定环境的版本 配置{EnvironmentName}和配置{EnvironmentName}形式的服务:

你可以这样做……

public void ConfigureProductionServices(IServiceCollection services)
{
    ConfigureCommonServices(services);
    
    //Services only for production
    services.Configure();
}

public void ConfigureDevelopmentServices(IServiceCollection services)
{
    ConfigureCommonServices(services);
    
    //Services only for development
    services.Configure();
}

public void ConfigureStagingServices(IServiceCollection services)
{
    ConfigureCommonServices(services);
    
    //Services only for staging
    services.Configure();
}

private void ConfigureCommonServices(IServiceCollection services)
{
    //Services common to each environment
}

以防有人也在看这个。在.net core 3+中，这些都已经过时了。更新方式为:

public void Configure(
    IApplicationBuilder app,
    IWebHostEnvironment env,
    ILogger<Startup> logger)
{
    if (env.EnvironmentName == Environments.Development)
    {
        // logger.LogInformation("In Development environment");
    }
}