C# ServiceCollection.TryAdd方法代码示例

        public void TryAddNoOpFailsIfExists(Action<IServiceCollection> addAction)
        {
            // Arrange
            var collection = new ServiceCollection();
            addAction(collection);
            var d = ServiceDescriptor.Transient<IFakeService, FakeService>();

            // Act
            collection.TryAdd(d);

            // Assert
            var descriptor = Assert.Single(collection);
            Assert.Equal(typeof(IFakeService), descriptor.ServiceType);
            Assert.Same(_instance, descriptor.ImplementationInstance);
            Assert.Equal(ServiceLifetime.Singleton, descriptor.Lifetime);
        }

        public void TryAddWithEnumerableReturnsTrueIfAnyAdded()
        {
            // Arrange
            var collection = new ServiceCollection();

            // Act
            var ds = new ServiceDescriptor[] {
                ServiceDescriptor.Transient<IFakeService, FakeService>(),
                ServiceDescriptor.Transient<IFakeService, FakeService>()
            };

            // Assert
            Assert.True(collection.TryAdd(ds));
            var descriptor = Assert.Single(collection);
            Assert.Equal(typeof(IFakeService), descriptor.ServiceType);
            Assert.Null(descriptor.ImplementationInstance);
            Assert.Equal(ServiceLifetime.Transient, descriptor.Lifetime);
        }

        public void TryAddIfMissingActuallyAdds()
        {
            // Arrange
            var collection = new ServiceCollection();
            var d = ServiceDescriptor.Transient<IFakeService, FakeService>();

            // Act
            collection.TryAdd(d);

            // Assert
            var descriptor = Assert.Single(collection);
            Assert.Equal(typeof(IFakeService), descriptor.ServiceType);
            Assert.Null(descriptor.ImplementationInstance);
            Assert.Equal(ServiceLifetime.Transient, descriptor.Lifetime);
        }

        public static IServiceCollection GetDefaultServices()
        {
            var services = new ServiceCollection();

            // Options and core services.
            services.AddTransient<IConfigureOptions<MvcOptions>, MvcOptionsSetup>();
            services.AddTransient<IConfigureOptions<RazorViewEngineOptions>, RazorViewEngineOptionsSetup>();

            // TryAdd() so functional tests can override this particular service. Test setup runs before this method.
            services.TryAdd(ServiceDescriptor.Transient<IAssemblyProvider, DefaultAssemblyProvider>());

            services.AddTransient<MvcMarkerService, MvcMarkerService>();
            services.AddSingleton<ITypeActivatorCache, DefaultTypeActivatorCache>();
            services.AddScoped(typeof(IScopedInstance<>), typeof(ScopedInstance<>));

            // Core action discovery, filters and action execution.

            // These are consumed only when creating action descriptors, then they can be de-allocated
            services.AddTransient<IControllerTypeProvider, DefaultControllerTypeProvider>();
            services.AddTransient<IControllerModelBuilder, DefaultControllerModelBuilder>();
            services.AddTransient<IActionModelBuilder, DefaultActionModelBuilder>();

            // This has a cache, so it needs to be a singleton
            services.AddSingleton<IControllerFactory, DefaultControllerFactory>();

            services.AddTransient<IControllerActivator, DefaultControllerActivator>();

            // This accesses per-reqest services
            services.AddTransient<IActionInvokerFactory, ActionInvokerFactory>();

            // This provider needs access to the per-request services, but might be used many times for a given
            // request.
            services.AddTransient<IActionConstraintProvider, DefaultActionConstraintProvider>();

            services.AddSingleton<IActionSelectorDecisionTreeProvider, ActionSelectorDecisionTreeProvider>();
            services.AddSingleton<IActionSelector, DefaultActionSelector>();
            services.AddTransient<IControllerActionArgumentBinder, DefaultControllerActionArgumentBinder>();
            services.AddTransient<IObjectModelValidator, DefaultObjectValidator>();

            services.AddTransient<IActionDescriptorProvider, ControllerActionDescriptorProvider>();

            services.AddTransient<IActionInvokerProvider, ControllerActionInvokerProvider>();

            services.AddSingleton<IActionDescriptorsCollectionProvider, DefaultActionDescriptorsCollectionProvider>();

            // The IGlobalFilterProvider is used to build the action descriptors (likely once) and so should
            // remain transient to avoid keeping it in memory.
            services.AddTransient<IGlobalFilterProvider, DefaultGlobalFilterProvider>();
            services.AddTransient<IFilterProvider, DefaultFilterProvider>();

            services.AddTransient<FormatFilter, FormatFilter>();
            services.AddTransient<CorsAuthorizationFilter, CorsAuthorizationFilter>();

            // Dataflow - ModelBinding, Validation and Formatting
            //
            // The DefaultModelMetadataProvider does significant caching and should be a singleton.
            services.AddSingleton<ModelBinding.IModelMetadataProvider, DefaultModelMetadataProvider>();
            services.AddTransient<ModelBinding.Metadata.ICompositeMetadataDetailsProvider>(serviceProvider =>
            {
                var options = serviceProvider.GetRequiredService<IOptions<MvcOptions>>().Options;
                return new DefaultCompositeMetadataDetailsProvider(options.ModelMetadataDetailsProviders);
            });

            services.AddTransient<IInputFormatterSelector, DefaultInputFormatterSelector>();
            services.AddScoped<IInputFormattersProvider, DefaultInputFormattersProvider>();

            services.AddTransient<IModelBinderProvider, DefaultModelBindersProvider>();
            services.AddTransient<IValueProviderFactoryProvider, DefaultValueProviderFactoryProvider>();
            services.AddTransient<IOutputFormattersProvider, DefaultOutputFormattersProvider>();
            services.AddInstance(new JsonOutputFormatter());

            services.AddTransient<IModelValidatorProviderProvider, DefaultModelValidatorProviderProvider>();
            services.AddTransient<IValidationExcludeFiltersProvider, DefaultValidationExcludeFiltersProvider>();

            // Razor, Views and runtime compilation

            // The provider is inexpensive to initialize and provides ViewEngines that may require request
            // specific services.
            services.AddScoped<ICompositeViewEngine, CompositeViewEngine>();
            services.AddTransient<IViewEngineProvider, DefaultViewEngineProvider>();
            // Transient since the IViewLocationExpanders returned by the instance is cached by view engines.
            services.AddTransient<IViewLocationExpanderProvider, DefaultViewLocationExpanderProvider>();
            // Caches view locations that are valid for the lifetime of the application.
            services.AddSingleton<IViewLocationCache, DefaultViewLocationCache>();
            services.AddSingleton<ICodeTreeCache>(serviceProvider =>
            {
                var cachedFileProvider = serviceProvider.GetRequiredService<IOptions<RazorViewEngineOptions>>();
                return new DefaultCodeTreeCache(cachedFileProvider.Options.FileProvider);
            });

            // The host is designed to be discarded after consumption and is very inexpensive to initialize.
            services.AddTransient<IMvcRazorHost, MvcRazorHost>();

            // Caches compilation artifacts across the lifetime of the application.
            services.AddSingleton<ICompilerCache, CompilerCache>();

            // This caches compilation related details that are valid across the lifetime of the application
            // and is required to be a singleton.
            services.AddSingleton<ICompilationService, RoslynCompilationService>();

//.........这里部分代码省略.........