Selecting OrderBy or OrderByDescending using a delegate
Linq to SQL has two methods to sort a query ascending or descending, respectively:
Sometimes, you want to have a SortDirection determining the sort order. You can do this by using a delegate:
public delegate IOrderedEnumerable<TSource> OrderFunc<TSource, TKey>(Func<TSource, TKey> keySelector); ... OrderFunc<Car, string> orderFunc; if (sortDirection == SortDirection.Ascending) orderFunc = matches.OrderBy; else orderFunc = matches.OrderByDescending; result = orderFunc(c => c.Wheels);
OrderFunc is the type of a variable, just like int or string. The variable orderFunc is of type OrderFunc. Instead of holding a value, it holds a reference to a method. In our case, that method is either OrderBy or OrderByDescending.