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";

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)
        {

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
}

我想在我的服务中加入这种环境。这真的很容易做到!我只是像这样把它注入到构造函数中:

    private readonly IHostingEnvironment _hostingEnvironment;

    public MyEmailService(IHostingEnvironment hostingEnvironment)
    {
        _hostingEnvironment = hostingEnvironment;
    }

现在在稍后的代码中，我可以这样做:

if (_hostingEnvironment.IsProduction()) {
    // really send the email.
}
else {
    // send the email to the test queue.
}

编辑:

上面的代码是用于。net Core 2的。对于版本3，您将使用IWebHostEnvironment。

在. net Core 2.0 MVC app / Microsoft.AspNetCore.All v2.0.0中，你可以有@vaindil所描述的特定于环境的启动类，但我不喜欢这种方法。

你也可以在StartUp构造函数中注入IHostingEnvironment。不需要将环境变量存储在Program类中。

public class Startup
{
    private readonly IHostingEnvironment _currentEnvironment;
    public IConfiguration Configuration { get; private set; }

    public Startup(IConfiguration configuration, IHostingEnvironment env)
    {
        _currentEnvironment = env;
        Configuration = configuration;
    }

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

        services.AddMvc(config =>
        {
            // Requiring authenticated users on the site globally
            var policy = new AuthorizationPolicyBuilder()
                .RequireAuthenticatedUser()
                .Build();
            config.Filters.Add(new AuthorizeFilter(policy));

            // Validate anti-forgery token globally
            config.Filters.Add(new AutoValidateAntiforgeryTokenAttribute());

            // If it's Production, enable HTTPS
            if (_currentEnvironment.IsProduction())      // <------
            {
                config.Filters.Add(new RequireHttpsAttribute());
            }            
        });

        ......
    }
}

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");
    }
}