Dashboard Jobs section throwing Object reference error

question
,
1

Hi there,

All of a sudden my Hangfire dashboard throws a “Object reference not set to an instance of an object.” error when trying to open the jobs area of the dashboard.

So i have 2 questions around this.

  1. How do i resolve the issue
  2. how to i delete job sitting in queue if i am not able to get into the dashboard? Is there a way to programatically force Hangfire to purge all jobs sitting in queue?
2

I would start by looking at the Windows Event log to find the stack trace where you are getting the null reference

3

Thanks for the reply. I’m not getting much direction from the event log or .net error. On the dashboard page the UI says there are 7 jobs queued and 2 failed. I can’t get much further than that. I’m working in a dev environment with Hangfire running on IISExpress as i debug my application in VS. You welcome to take a peak:

Exception information:
Exception type: NullReferenceException
Exception message: Object reference not set to an instance of an object.
at Hangfire.Dashboard.Pages.QueuesPage.Execute()
at Hangfire.Dashboard.RazorPage.TransformText(String body)
at Hangfire.Dashboard.RazorPage.ToString()
at Hangfire.Dashboard.RazorPageDispatcher.Dispatch(RequestDispatcherContext context)
at Hangfire.Dashboard.MiddlewareExtensions.<>c__DisplayClass6.<>c__DisplayClass8.b__4(IDictionary`2 env)
at Microsoft.Owin.Infrastructure.AppFuncTransition.Invoke(IOwinContext context)
at Microsoft.Owin.Mapping.MapMiddleware.d__0.MoveNext()
— End of stack trace from previous location where exception was thrown —
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.IntegratedPipelineContextStage.d__5.MoveNext()
— End of stack trace from previous location where exception was thrown —
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.IntegratedPipelineContext.d__2.MoveNext()
— End of stack trace from previous location where exception was thrown —
at Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.StageAsyncResult.End(IAsyncResult ar)
at Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.IntegratedPipelineContext.EndFinalWork(IAsyncResult ar)
at System.Web.HttpApplication.AsyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

…

Object reference not set to an instance of an object. at Hangfire.Dashboard.Pages.QueuesPage.Execute() at Hangfire.Dashboard.RazorPage.TransformText(String body) at Hangfire.Dashboard.RazorPage.ToString() at Hangfire.Dashboard.RazorPageDispatcher.Dispatch(RequestDispatcherContext context) at Hangfire.Dashboard.MiddlewareExtensions.<>c__DisplayClass6.<>c__DisplayClass8.b__4(IDictionary`2 env) at Microsoft.Owin.Infrastructure.AppFuncTransition.Invoke(IOwinContext context) at Microsoft.Owin.Mapping.MapMiddleware.d__0.MoveNext() — End of stack trace from previous location where exception was thrown — at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.IntegratedPipelineContextStage.d__5.MoveNext() — End of stack trace from previous location where exception was thrown — at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.IntegratedPipelineContext.d__2.MoveNext() — End of stack trace from previous location where exception was thrown — at Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.StageAsyncResult.End(IAsyncResult ar) at Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.IntegratedPipelineContext.EndFinalWork(IAsyncResult ar) at System.Web.HttpApplication.AsyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)
http://localhost:50593/hangfire/jobs/enqueued
/hangfire/jobs/enqueued
::1

False

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False
at Hangfire.Dashboard.Pages.QueuesPage.Execute() at Hangfire.Dashboard.RazorPage.TransformText(String body) at Hangfire.Dashboard.RazorPage.ToString() at Hangfire.Dashboard.RazorPageDispatcher.Dispatch(RequestDispatcherContext context) at Hangfire.Dashboard.MiddlewareExtensions.<>c__DisplayClass6.<>c__DisplayClass8.b__4(IDictionary`2 env) at Microsoft.Owin.Infrastructure.AppFuncTransition.Invoke(IOwinContext context) at Microsoft.Owin.Mapping.MapMiddleware.d__0.MoveNext() — End of stack trace from previous location where exception was thrown — at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.IntegratedPipelineContextStage.d__5.MoveNext() — End of stack trace from previous location where exception was thrown — at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.IntegratedPipelineContext.d__2.MoveNext() — End of stack trace from previous location where exception was thrown — at Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.StageAsyncResult.End(IAsyncResult ar) at Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.IntegratedPipelineContext.EndFinalWork(IAsyncResult ar) at System.Web.HttpApplication.AsyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)