Distinct() with lambda?

Question

Right, so I have an enumerable and wish to get distinct values from it.

Using System.Linq, there\'s of course an extension method called Distinct<

Answer 1

It looks to me like you want DistinctBy from MoreLINQ. You can then write:

var distinctValues = myCustomerList.DistinctBy(c => c.CustomerId);

Here's a cut-down version of DistinctBy (no nullity checking and no option to specify your own key comparer):

public static IEnumerable DistinctBy
     (this IEnumerable source, Func keySelector)
{
    HashSet knownKeys = new HashSet();
    foreach (TSource element in source)
    {
        if (knownKeys.Add(keySelector(element)))
        {
            yield return element;
        }
    }
}