每个匹配生命周期范围的实例，默认情况下？

我想在Autofac中为每个匹配的生命周期范围注册创建一个实例，但偶尔需要从全局容器（没有匹配的生命周期范围）请求实例。 在没有匹配的生命周期范围的情况下，我想提供一个顶级实例而不是抛出exception。

这可能吗？

Answer 1

我认为你最好通过引入一个新的生命期选项来扩展Autofac。 我使用了Autofac源并对其进行了一些修改：

public static class RegistrationBuilderExtensions { public static IRegistrationBuilder InstancePerMatchingOrRootLifetimeScope(this IRegistrationBuilder builder, params object[] lifetimeScopeTag) { if (lifetimeScopeTag == null) throw new ArgumentNullException("lifetimeScopeTag"); builder.RegistrationData.Sharing = InstanceSharing.Shared; builder.RegistrationData.Lifetime = new MatchingScopeOrRootLifetime(lifetimeScopeTag); return builder; } } public class MatchingScopeOrRootLifetime: IComponentLifetime { readonly object[] _tagsToMatch; public MatchingScopeOrRootLifetime(params object[] lifetimeScopeTagsToMatch) { if (lifetimeScopeTagsToMatch == null) throw new ArgumentNullException("lifetimeScopeTagsToMatch"); _tagsToMatch = lifetimeScopeTagsToMatch; } public ISharingLifetimeScope FindScope(ISharingLifetimeScope mostNestedVisibleScope) { if (mostNestedVisibleScope == null) throw new ArgumentNullException("mostNestedVisibleScope"); var next = mostNestedVisibleScope; while (next != null) { if (_tagsToMatch.Contains(next.Tag)) return next; next = next.ParentLifetimeScope; } return mostNestedVisibleScope.RootLifetimeScope; } } 

只需将这些类添加到项目中，并将组件注册为：

 builder.RegisterType.InstancePerMatchingOrRootLifetimeScope("TAG"); 

我自己没试过，但它应该有用。

Answer 2

可能的解决方案是覆盖子生命周期范围内的注册。

样品：

 public enum Scopes { TestScope } public class Test { public string Description { get; set; } } public class Tester { public void DoTest() { ContainerBuilder builder = new ContainerBuilder(); builder.RegisterType() .OnActivating(args => args.Instance.Description = "FromRoot") .SingleInstance(); var container = builder.Build(); var scope = container.BeginLifetimeScope(Scopes.TestScope, b => b .RegisterType() .InstancePerMatchingLifetimeScope(Scopes.TestScope) .OnActivating(args => args.Instance.Description = "FromScope")); var test1 = container.Resolve(); Console.WriteLine(test1.Description); //writes FromRoot var test2 = scope.Resolve(); Console.WriteLine(test2.Description); //writes FromScope Console.ReadLine(); } }