Aggregate
Since System.Linq.Enumerable.Aggregate throws a System.InvalidOperationException in case the given list is empty you can't use this function in a complex linq expression. This aggregate version simply returns a defaultvalue if the list is empty
Source
namespace ExtensionMethods
{
public static class Enumerable
{
public static T Aggregate<T>(
this IEnumerable<T> list, Func<T, T, T> aggregateFunction)
{
return Aggregate<T>(list, default(T), aggregateFunction);
}
public static T Aggregate<T>(this IEnumerable<T> list, T defaultValue,
Func<T, T, T> aggregateFunction)
{
return list.Count() <= 0 ?
defaultValue : list.Aggregate<T>(aggregateFunction);
}
}
}
Example
return ( from x in _map.Keys
where CheckValue(x)
select _map[x]). Aggregate(MyFlags.None, (x, y) => x | y);
Author: RW
Submitted on: 18 feb. 2009
Language: C#
Type: System.Collections.Generic.IEnumerable<T>
Views: 8090