Question

I have a thread that loads data when a service is starting. I call a method in this thread that uses Parallel.Foreach to iterate a set of data. But the linq query that I have inside the parallel forerach, gets a objet reference not set to an instance error.

*The same logic works if I remove the Parallel.Foreach though or if I remove the thread. *Even locking the list doesnt help.**

    loadingThread = new Thread(new ThreadStart(PreloadData));
                loadingThread.IsBackground = true;
                loadingThread.Start();
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    public static void PreloadData()
    {
     Parallel.ForEach(loadedIDs.Keys, indexDefId =>
                    {
                        List<FixingEvent> lst = null;
                        lock (loadedEvents)
                        {
                            lst = (from e in loadedEvents where e.DIVACode.Equals(indexDefId) select e).ToList();
                        }

---------------------------
    }

I get an exception in the linq query inside – ‘ e is null and hence object reference error’.

Any help is appreciated.

Answer 1

I guess the list loadedEvents contains null elements. Maybe due to a race condition.