getting argument exception in concurrent dictionary when sorting and displaying as it is being updated

Question

I am getting a hard to reproduce error in the following program in which a number of threads update a concurrent dictionary in parallel and the main thread displays the stat

Answer 1

After a discussion with ChrisShain in the comments, the conclusion is that you should get mutually exclusive access to the dictionary before printing it out, either with a mutex of a lock statement.

Doing it with a lock:

public void WriteBatch(IEnumerable> batch)
{
    lock (myLock) 
    {
        foreach (var tuple in batch)
        {
            Console.WriteLine("{0} - {1}", tuple.Item1, tuple.Item2);
        }
        Console.WriteLine();
    }
}

assuming you allocated a myLock object at the class level. See example.

Doing it with a mutex:

public void WriteBatch(IEnumerable> batch)
{
    mut.WaitOne();

    foreach (var tuple in batch)
    {
        Console.WriteLine("{0} - {1}", tuple.Item1, tuple.Item2);
    }
    Console.WriteLine();

    mut.ReleaseMutex();
}

Again, assuming you allocated a Mutex object at the class level. See example.