c# - 如何将方面应用于特定元素(例如，对于 LocationInfo 类型参数或 PropertyInfo)？

Question

TL/DR:

如何将 Aspect 应用于特定元素，例如对于 LocationInfo 类型参数，或 PropertyInfo ？

详细说明:

我想在RuntimeInitialize期间找到属性/字段的所有依赖项

[Serializable]
public class NotifyPropertyChangedAspect : LocationInterceptionAspect {
    /* ... stuff ... */
    public override void RuntimeInitialize(LocationInfo locationInfo)
    {
        foreach(var attr in locationInfo.PropertyInfo.GetCustomAttributes(false)
                                .OfType<DependsOnAttribute>();){
            this.SaveDependencies(attr.Dependencies);
        }
        base.RuntimeInitialize(locationInfo);
    }
    /* ... things ... */
}

上面的代码适用于属性:

[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field)]
public class DependsOnAttribute : Attribute {
    public string[] Dependencies { get; set; }
    public DependsOnAttribute(params string[] dependencies) { Dependencies = dependencies; }
}

[NotifyPropertyChangedAspect]
class MyClass {
    public string Name { get; set; }
    [DependsOnAttribute("Name")]
    public bool IsChanged { get; set; }
}

但不适用于方面:

[Serializable]
public class DependsOnAspect : LocationLevelAspect {
    public string[] Dependencies { get; set; }
    public DependsOnAspect(params string[] dependencies) { Dependencies = dependencies; }
}

[NotifyPropertyChangedAspect]
class MyClass {
    public string Name { get; set; }
    [DependsOnAspect("Name")]
    public bool IsChanged { get; set; }
}

Answer 1

方面是多播属性的特例。简而言之，在 PostSharp 处理程序集后，多播属性将从程序集中删除。要覆盖此行为，您需要指定以下内容:

[MulticastAttributeUsage(PersistMetaData = true)]
public class DependsOnAspect : LocationLevelAspect { ... }

这将告诉 PostSharp 您需要在运行时提供方面属性。