Recreating a Dictionary from an IEnumerable<KeyValuePair<>>

Question

I have a method that returns an IEnumerable<KeyValuePair<string, ArrayList>>, but some of the callers require the result of the method to be a dictionary. How can I convert the IEnumerable<KeyValuePair<string, ArrayList>> into a Dictionary<string, ArrayList> so that I can use TryGetValue?

method:

public IEnumerable<KeyValuePair<string, ArrayList>> GetComponents()
{
  // ...
  yield return new KeyValuePair<string, ArrayList>(t.Name, controlInformation);
}

caller:

Dictionary<string, ArrayList> actual = target.GetComponents();
actual.ContainsKey("something");

Jon Skeet Jon Skeet · Accepted Answer · 2010-04-14T10:35:47

If you're using .NET 3.5 or .NET 4, it's easy to create the dictionary using LINQ:

Dictionary<string, ArrayList> result = target.GetComponents()
                                      .ToDictionary(x => x.Key, x => x.Value);

There's no such thing as an IEnumerable<T1, T2> but a KeyValuePair<TKey, TValue> is fine.

Recreating a Dictionary from an IEnumerable<KeyValuePair<>>

2 Answers