Question

Code:

    List<Item> Contents = ObjectHandler.player.Contents.ToList<Item>() //Was HashTable
    List<int> IDS = new List<int>(); //Holds Item IDs for later counting
    foreach (Item I in Contents) 
    {
        IDS.Add(I.ID); // Add ID to IDS
    }
    List<Item> newContents = Contents;
    foreach (Item I in Contents)
    {
        if (IDS.Contains(I.ID)) //Check if the ID has already been used in Contents
        {
            newContents.Remove(I); //Remove it
        }
    }
    Contents = newContents;

This Code snippet should prepare a list of IDs for later counting, and also remove duplicates from a list of Items. However, as soon as an item is present in Contents, however, I recieve an InvalidOperationException. I’m fairly certain I’m not modifying Contents, which the foreach is looping through, thus my confusion. Could somebody explain this to me? thanks.

Answer 1

newContents = Contents;

You now have two variables pointing to the same collection.

You probably want to copy the collection by writing new List<Item>(Contents).