c# - IEnumerable<T >'requires ' 1' 类型参数

Question

为了更改提供给我们的 dll，我使用了 IAspectProvider 接口(interface)并满足其所需的 ProvideAspects 方法。作为

public class TraceAspectProvider : IAspectProvider {
    readonly SomeTracingAspect aspectToApply = new SomeTracingAspect();

    public IEnumerable ProvideAspects(object targetElement) {
        Assembly assembly = (Assembly)targetElement;
        List instances = new List();
        foreach (Type type in assembly.GetTypes()) {
            ProcessType(type, instances);
        }
        return instances;
    }
    void ProcessType(Type type, List instances) {
        foreach (MethodInfo targetMethod in type.GetMethods(BindingFlags.Instance | BindingFlags.Public | BindingFlags.DeclaredOnly)) {
            instances.Add(new AspectInstance(targetMethod, aspectToApply));
        }
        foreach (Type nestedType in type.GetNestedTypes()) {
            ProcessType(nestedType, instances);
        }
    }
}

运行时出现这些错误

等待您的宝贵意见

Answer 1

如果你看the documentation for ProvideAspects() , 你会注意到它返回 IEnumerable<AspectInstance> ，所以这也是您必须在代码中使用的内容:

public class TraceAspectProvider : IAspectProvider {
    readonly SomeTracingAspect aspectToApply = new SomeTracingAspect();

    public IEnumerable<AspectInstance> ProvideAspects(object targetElement) {
        Assembly assembly = (Assembly)targetElement;
        List<AspectInstance> instances = new List<AspectInstance>();
        foreach (Type type in assembly.GetTypes()) {
            ProcessType(type, instances);
        }
        return instances;
    }
    void ProcessType(Type type, List<AspectInstance> instances) {
        foreach (MethodInfo targetMethod in type.GetMethods(BindingFlags.Instance | BindingFlags.Public | BindingFlags.DeclaredOnly)) {
            instances.Add(new AspectInstance(targetMethod, aspectToApply));
        }
        foreach (Type nestedType in type.GetNestedTypes()) {
            ProcessType(nestedType, instances);
        }
    }
}