Question

I want to create a method that would iterate through a keyed collection. I want to make sure that my method support iteration of any collection that extends the KeyedCollection<string, Collection<string>>

Here’s the method:

public void IterateCollection(KeyedCollection<string, Collection<string>> items)
{
    foreach (??? item in items)
    {
        Console.WriteLine("Key: " + item.Key);
        Console.WriteLine("Value: " + item.Value);
    }
}

It doesn’t work obviously because I don’t know which type should replace the question marks in the loop. I cannot simply put object or var because I need to call the Key and Value properties later on in the loop body. What is the type that I am looking for? Thanks.

Answer 1

KeyedCollection<TKey, TItem> implements ICollection<TItem>, so in this case you’d use:

foreach(Collection<string> item in items)

That’s what var would give you as well. You don’t get key/value pairs in KeyedCollection – you just get the values.

Is it possible that KeyedCollection really isn’t the most appropriate type for you to be using?