/// <summary>
/// Updates the old collection with new items, while removing the inexistent.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="old"></param>
/// <param name="fresh"></param>
/// <returns></returns>
public static void Update <T>(this IList <T> old, IEnumerable <T> fresh) where T : IEquatable <T>
{
if (old == null)
{
throw new ArgumentNullException("old");
}
if (fresh == null)
{
throw new ArgumentNullException("fresh");
}
var diff = fresh.Diff(old);
foreach (var item in diff.Removed)
{
old.Remove(item);
}
foreach (var item in diff.Added)
{
old.Add(item);
}
}