从 Singleton 使用 Scoped 服务

Question

在使用来自单例的作用域时，我没有收到任何错误

根据下面的文章，我应该在启动服务后立即收到错误消息： https://dotnetcoretutorials.com/2018/03/20/cannot-consume-scoped-service-from-singleton-a-lesson-in-asp-net-core-di-scopes/

依赖注册：

builder.Services.AddScoped<ILogger, AppLogs>();
            builder.Services.AddSingleton<ICacheFactory>(x =>
            {
                string cacheConnectionString = "xyz";
                return new CacheFactory(cacheConnectionString, x.GetService<ILogger>());
            });

消耗：

    public class Function1
    {
        private readonly ICacheFactory cacheProvider;
        public Function1(ICacheFactory cacheProvider) {
            this.cacheProvider = cacheProvider;
        }


        [FunctionName("Function1")]
        public  async Task<IActionResult> Run(
            [HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)] HttpRequest req,
            ILogger log)
        {


            var result = await this.cacheProvider.GetResultsAsync<IEnumerable<string>>("abc").ConfigureAwait(false);}
}

单例中的作用域注入何时会产生问题？

Answer 1

要在单例实例中使用作用域服务时出现错误，您必须在构建服务提供者时将 ValidateScopes 选项设置为 true，例如

var provider = services.BuildServiceProvider(validateScopes: true);

验证有点昂贵，因此您可以将其更改为仅在您这样开发时进行验证：

var provider = services.BuildServiceProvider(validateScopes: Debugger.IsAttached);

Documentation on BuildServiceProvider