Question

I am using extension methods OrderBy and ThenBy to sort my custom collection on multiple fields. This sort does not effect the collection but instead returns and IEnumberable. I am unable to cast the IEnumerable result to my custom collection. Is there anyway to change the order of my collection or convert the IEnumerable result to my custom collection?

Answer 1

If your collection type implements IList<T> (to be able to Add() to it) you could write an extension method:

public static Extensions
{
    public static TColl ToTypedCollection<TColl, T>(this IEnumerable ien)
        where TColl : IList<T>, new()
    {
        TColl collection = new TColl();

        foreach (var item in ien)
        {
            collection.Add((T) item);
        }

        return collection;
    }
}