【问题标题】：Does the OnActionExecuted method of an attribute always execute?属性的 OnActionExecuted 方法是否始终执行？
【发布时间】：2010-12-11 15:05:59
【问题描述】：

我从高处和低处搜索过，但似乎找不到一个直接的答案。

如果我有一个自定义属性/过滤器，OnActionExecuted 方法是否总是被调用？即使抛出异常？

【问题讨论】：

标签： asp.net-mvc attributes

【解决方案1】：

至少对于 MVC 5，@tvanfosson 的答案不再正确。这也可能适用于早期版本。

OnActionExecuted 总是被调用并且可以通过filterContext.Exception 访问抛出的异常。

动作中出现异常的测试用例：

public class HomeController
    : Controller
{
    public ActionResult Index()
    {
        throw new Exception("Index");
    }
}

public class FilterConfig
{
    public static void RegisterGlobalFilters(GlobalFilterCollection filters)
    {
        filters.Add(new Foo());
        filters.Add(new Bar());
    }
}

public class Foo
    : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        Debug.WriteLine($"{nameof(Foo)}.{nameof(OnActionExecuting)}");
        base.OnActionExecuting(filterContext);
    }

    public override void OnActionExecuted(ActionExecutedContext filterContext)
    {
        Debug.WriteLine($"{nameof(Foo)}.{nameof(OnActionExecuted)}");
        Debug.WriteLine($"Has exception: {filterContext.Exception != null}");
        base.OnActionExecuted(filterContext);
    }
}

public class Bar
    : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        Debug.WriteLine($"{nameof(Bar)}.{nameof(OnActionExecuting)}");
        base.OnActionExecuting(filterContext);
    }

    public override void OnActionExecuted(ActionExecutedContext filterContext)
    {
        Debug.WriteLine($"{nameof(Bar)}.{nameof(OnActionExecuted)}");
        Debug.WriteLine($"Has exception: {filterContext.Exception != null}");
        base.OnActionExecuted(filterContext);
    }
}

输出：

Bar.OnActionExecuting
Foo.OnActionExecuting
Exception thrown: 'System.Exception' in WebApplication1.dll
Foo.OnActionExecuted
Has exception: True
Bar.OnActionExecuted
Has exception: True

过滤器中有异常的测试用例

public class HomeController
    : Controller
{
    public ActionResult Index()
    {
        return new HttpStatusCodeResult(200);
    }
}

public class FilterConfig
{
    public static void RegisterGlobalFilters(GlobalFilterCollection filters)
    {
        filters.Add(new Foo());
        filters.Add(new Bar());
    }
}

public class Foo
    : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        Debug.WriteLine($"{nameof(Foo)}.{nameof(OnActionExecuting)}");
        base.OnActionExecuting(filterContext);
    }

    public override void OnActionExecuted(ActionExecutedContext filterContext)
    {
        Debug.WriteLine($"{nameof(Foo)}.{nameof(OnActionExecuted)}");
        Debug.WriteLine($"Has exception: {filterContext.Exception != null}");
        throw new Exception("Foo");
        base.OnActionExecuted(filterContext);
    }
}

public class Bar
    : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        Debug.WriteLine($"{nameof(Bar)}.{nameof(OnActionExecuting)}");
        base.OnActionExecuting(filterContext);
    }

    public override void OnActionExecuted(ActionExecutedContext filterContext)
    {
        Debug.WriteLine($"{nameof(Bar)}.{nameof(OnActionExecuted)}");
        Debug.WriteLine($"Has exception: {filterContext.Exception != null}");
        base.OnActionExecuted(filterContext);
    }
}

输出：

Bar.OnActionExecuting
Foo.OnActionExecuting
Foo.OnActionExecuted
Has exception: False
Exception thrown: 'System.Exception' in WebApplication1.dll
Bar.OnActionExecuted
Has exception: True

【讨论】：

感谢您为 MVC 5 更新此内容！
那么，MVC
我可以确认 MVC 4 也是如此。