C# ASP MVC过滤器，在哪里实现接口？

只是想知道，谷歌搜索如何在asp mvc 4中使用过滤器。我发现有些人这样定义他们：

public class CustomFilter : ActionFilterAttribute

public class CustomFilter : ActionFilterAttribute, IActionFilter

有些是这样的：

public class CustomFilter : ActionFilterAttribute

public class CustomFilter : ActionFilterAttribute, IActionFilter

ActionFilterAttribute已经有了所有要重写的操作，为什么还要实现该接口呢

例如，在下一个代码中，在最后再次调用过滤器，这是为什么

public class 

CustomActionFilter : ActionFilterAttribute, IActionFilter
{
    void IActionFilter.OnActionExecuting(ActionExecutingContext filterContext)


    {
        // TODO: Add your acction filter's tasks here

        // Log Action Filter Call
        MusicStoreEntities storeDB = new MusicStoreEntities();

        ActionLog log = new ActionLog()
        {
            Controller = filterContext.ActionDescriptor.ControllerDescriptor.ControllerName,
            Action = filterContext.ActionDescriptor.ActionName + " (Logged By: Custom 

Action Filter)",
            IP = filterContext.HttpContext.Request.UserHostAddress,
            DateTime = filterContext.HttpContext.Timestamp
        };

        storeDB.ActionLogs.Add(log);
        storeDB.SaveChanges();

        this.OnActionExecuting(filterContext);
    }
}

如果选中，您将看到它是一个抽象类，继承了IActionFilter和IResultFilter接口

实际上继承自ActionFilterAttribute

相当于继承类FilterAttribute和接口IActionFilter和IResultFilter

这和

public class CustomFilter : ActionFilterAttribute, IActionFilter, IResultFilter

---

因此，从ActionFilterAttribute继承与从ActionFilterAttribute和IActionFilter继承没有什么不同。

但似乎是多余的，不是吗？那么从ActionFilterAttribute继承就足够了？@user1777914，完全多余。是，ActionFilterAttribute是整个软件包。