堆栈跟踪在有两个时意味着什么?

时间:2012-05-08 12:40:55

标签: asp.net asp.net-mvc-3

我有一个MVC应用程序,它基本上有两个堆栈跟踪,我想知道为什么有两个呢?...

[MissingMethodException: No parameterless constructor defined for this object.]
   System.RuntimeTypeHandle.CreateInstance(RuntimeType type, Boolean publicOnly, Boolean noCheck, Boolean& canBeCached, RuntimeMethodHandleInternal& ctor, Boolean& bNeedSecurityCheck) +0
   System.RuntimeType.CreateInstanceSlow(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache) +98
   System.RuntimeType.CreateInstanceDefaultCtor(Boolean publicOnly, Boolean skipVisibilityChecks, Boolean skipCheckThis, Boolean fillCache) +241
   System.Activator.CreateInstance(Type type, Boolean nonPublic) +69
   System.Web.Mvc.DefaultControllerActivator.Create(RequestContext requestContext, Type controllerType) +67

[InvalidOperationException: An error occurred when trying to create a controller of type 'PteDotNet.Web.Controllers.BlogController'. Make sure that the controller has a parameterless public constructor.]
   System.Web.Mvc.DefaultControllerActivator.Create(RequestContext requestContext, Type controllerType) +182
   System.Web.Mvc.DefaultControllerFactory.GetControllerInstance(RequestContext requestContext, Type controllerType) +80
   System.Web.Mvc.DefaultControllerFactory.CreateController(RequestContext requestContext, String controllerName) +74
   System.Web.Mvc.MvcHandler.ProcessRequestInit(HttpContextBase httpContext, IController& controller, IControllerFactory& factory) +232
   System.Web.Mvc.<>c__DisplayClass6.<BeginProcessRequest>b__2() +49
   System.Web.Mvc.<>c__DisplayClassb`1.<ProcessInApplicationTrust>b__a() +13
   System.Web.Mvc.SecurityUtil.<GetCallInAppTrustThunk>b__0(Action f) +7
   System.Web.Mvc.SecurityUtil.ProcessInApplicationTrust(Action action) +22
   System.Web.Mvc.SecurityUtil.ProcessInApplicationTrust(Func`1 func) +124
   System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContextBase httpContext, AsyncCallback callback, Object state) +98
   System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContext httpContext, AsyncCallback callback, Object state) +50
   System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.BeginProcessRequest(HttpContext context, AsyncCallback cb, Object extraData) +16
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +8970356
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +184

3 个答案:

答案 0 :(得分:0)

一个是内部异常的堆栈跟踪。

看起来你第一次得到MissingMethodException,原因是

  

没有为此对象定义无参数构造函数。

导致InvalidOperationException,原因

  

尝试创建“PteDotNet.Web.Controllers.BlogController”类型的控制器时发生错误。确保控制器具有无参数的公共构造函数。

显然你的BlogController需要一个无参数的构造函数。

答案 1 :(得分:0)

我不完全确定,但它看起来像根本原因:

首先触发MissingMethodException,然后InvalidOperationException被解雇,因为第一个受到了外来因素

答案 2 :(得分:0)

InvalidOperationException是抛出的异常,但由于MissingMethodException而被抛出,此异常包含在InnerException的{​​{1}}中。 InvalidOperationException解释了出现了什么问题,但查看了InvalidOperationException,您可以看到首先触发故障的位置。

当您对具有内部异常的异常评估InnerException时,您将获得所有嵌套内部异常的堆栈跟踪,以帮助您理解该问题。一个常见的错误是使用ToString()进行诊断,但是您丢失了有关内部异常的信息。除非您想隐藏这些有价值的信息,否则在记录异常时应始终使用ex.Message + ex.StackTrace

在MVC框架中有类似的代码:

ex.ToString()

因此,您可以获得try { // Will throw MissingMethodException if there is no parameterless constructor. var controller = Activator.CreateInstance(type); ... } catch (MissingMethodException ex) { var message = String.Format("An error occurred when trying to create a controller of type '{0}'. Make sure that the controller has a parameterless public constructor.", type); throw new InvalidOperationException(message, ex); } 一个很好的解释,而不是让MissingMethodException感到困惑。这是异常处理的最佳实践示例。