一. ControllerDescriptor说明
ControllerDescriptor是一个抽象类，它定义的接口代码如下：
public abstract class ControllerDescriptor : ICustomAttributeProvider, IUniquelyIdentifiable { public abstract ActionDescriptor FindAction(ControllerContext controllerContext, string actionName); public virtual object[] GetCustomAttributes(bool inherit); public virtual object[] GetCustomAttributes(Type attributeType, bool inherit); public virtual IEnumerable<FilterAttribute> GetFilterAttributes(bool useCache); public virtual bool IsDefined(Type attributeType, bool inherit); }