Question

Here is what I am trying to do:

        private readonly IDictionary<float, ICollection<IGameObjectController>> layers;

        foreach (ICollection<IGameObjectController> layerSet in layers.Values)
        {
            foreach (IGameObjectController controller in layerSet)
            {
                if (controller.Model.DefinedInVariant)
                {
                    layerSet.Remove(controller);
                }
            }
        }

Of course, this doesn’t work, because it will cause a concurrent modification exception. (Is there an equivalent of Java’s safe removal operation on some iterators?) How can I do this correctly, or with LINQ?

Answer 1

Use ToList to create an indpendent list over which to enumerate items to be removed.

    foreach (ICollection<IGameObjectController> layerSet in layers.Values)
    {
        foreach (IGameObjectController controller in layerSet
                   .Where(c => c.Model.DefinedInVariant).ToList())
        {
            layerSet.Remove(controller);

        }
    }