Extension Method of the Day: OrderBy with a Descending Flag
The title should say it all. Not sure why this didn’t make it into the System.Linq.Enumerable class, but this seems like a no-brainer. You need to sort a collection, but whether you sort ascending or descending is determined by a boolean argument instead of having to call a different method for each scenario. Add this to your collection utilities class immediately:
/// <summary> /// Sorts the elements of a sequence according to a key. /// </summary> /// <exception cref="System.ArgumentNullException">source or keySelector is null.</exception> /// <typeparam name="TSource">The type of the elements of source.</typeparam> /// <typeparam name="TKey">The type of the key returned by keySelector.</typeparam> /// <param name="source">A sequence of values to order.</param> /// <param name="keySelector">A function to extract a key from an element.</param> /// <param name="descending">if set to <c>true</c>, sorts the elements in descending order; otherwise in ascending order.</param> /// <returns>An System.Linq.IOrderedEnumerable<TElement> whose elements are sorted according to a key.</returns> public static IOrderedEnumerable<TSource> OrderBy<TSource, TKey>(this IEnumerable<TSource> source, Func<TSource, TKey> keySelector, bool descending) { if (descending) return source.OrderByDescending(keySelector); return source.OrderBy(keySelector); }
May 26th, 2010 at 1:26 am
nice one.
I’m always looking for new ways to do things,
can you provide your favorite way of implementing
and using such a collection utilities class
and a litte example for this OrderBy?
thanks