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)请求一个实例。在不存在匹配生命周期范围的情况下,我想给出一个顶级实例而不是抛出异常。
这可能吗?
最佳答案
我认为您最好通过引入新的生命周期选项来扩展 Autofac。我获取了 Autofac 源代码并对其进行了一些修改:
public static class RegistrationBuilderExtensions
{
public static IRegistrationBuilder<TLimit, TActivatorData, TRegistrationStyle> InstancePerMatchingOrRootLifetimeScope<TLimit, TActivatorData, TRegistrationStyle>(this IRegistrationBuilder<TLimit, TActivatorData, TRegistrationStyle> 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您的项目并将您的组件注册为:
builder.RegisterType<A>.InstancePerMatchingOrRootLifetimeScope("TAG");
我自己没试过,但应该可以。
关于c# - 每个匹配生命周期范围的实例,默认?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/14672541/