Odd exception coming from IncrementalLoadingCollection WinRT app

Question

Bugsense is telling me that I am getting a lot of exceptions like with this, in my WinRT Phone application

title:

A Task's exception(s) were not observed either by Waiting on the Task or accessing its Exception property. As a result, the unobserved exception was rethrown by the finalizer thread.

and this stackstrace:

    0 System.AggregateException: A Task's exception(s) were not observed either by Waiting on the Task or accessing its Exception property. As a result, the unobserved exception was rethrown by the finalizer thread. ---> System.NullReferenceException: Object reference not set to an instance of an object.           

 1 at ABC.Core.IncrementalLoadingCollection`1.<>c__DisplayClass20_0.<<LoadMoreItemsAsync>b__0>d.MoveNext()
    2 --- End of inner exception stack trace ---
    3---> (Inner Exception #0) System.NullReferenceException: Object reference not set to an instance of an object.
    4 at ABC.Core.IncrementalLoadingCollection`1.<>c__DisplayClass20_0.<<LoadMoreItemsAsync>b__0>d.MoveNext()<---
    5
    6--- Inner exception of type System.NullReferenceException start ---
    7--- Message: Object reference not set to an instance of an object. ---
    8System.NullReferenceException: Object reference not set to an instance of an object.
    9 at ABC.Core.IncrementalLoadingCollection`1.<>c__DisplayClass20_0.<<LoadMoreItemsAsync>b__0>d.MoveNext()
    10--- End of inner exception stack trace ---

Has anyone ever had this before? Should I move IncrementalLoadingCollection into the main app and not have the class in a seperate dll?

Peter Torr - MSFT Peter Torr - MSFT · Accepted Answer · 2015-09-23T00:52:17

Being in a DLL shouldn't matter; you should turn on 1st-chance exceptions in order to figure out where the exception is happening and to fix it - something is obviously null when it shouldn't be. You can turn on 1st-chance exceptions via the Debug -> Exceptions dialog and checking the Thrown column.

Also, as a general practice you shouldn't have async methods that don't protect themselves against exceptions (or that don't explicitly rely on their caller to do so).

Odd exception coming from IncrementalLoadingCollection WinRT app

1 Answers