ExtensionMethod.NET Home of 880 C#, Visual Basic, F# and Javascript extension methods

OrderBy

OrderBy is nice, except if you want to sort by multiple properties or want an easy way to distinguish between ascending and descending.

Source

public static IOrderedEnumerable<TSource> OrderBy<TSource, TKey>(this IEnumerable<TSource> enumerable, Func<TSource, TKey> keySelector, bool descending)
{
    if (enumerable == null)
    {
        return null;
    }

    if (descending)
    {
        return enumerable.OrderByDescending(keySelector);
    }

    return enumerable.OrderBy(keySelector);
}

public static IOrderedEnumerable<TSource> OrderBy<TSource>(this IEnumerable<TSource> enumerable, Func<TSource, IComparable> keySelector1, Func<TSource, IComparable> keySelector2, params Func<TSource, IComparable>[] keySelectors)
{
    if (enumerable == null)
    {
        return null;
    }

    IEnumerable<TSource> current = enumerable;

    if (keySelectors != null)
    {
        for (int i = keySelectors.Length - 1; i >= 0; i--)
        {
            current = current.OrderBy(keySelectors[i]);
        }
    }

    current = current.OrderBy(keySelector2);

    return current.OrderBy(keySelector1);
}

public static IOrderedEnumerable<TSource> OrderBy<TSource>(this IEnumerable<TSource> enumerable, bool descending, Func<TSource, IComparable> keySelector, params Func<TSource, IComparable>[] keySelectors)
{
    if (enumerable == null)
    {
        return null;
    }

    IEnumerable<TSource> current = enumerable;
    
    if (keySelectors != null)
    {
        for (int i = keySelectors.Length - 1; i >= 0; i--)
        {
            current = current.OrderBy(keySelectors[i], descending);
        }
    }

    return current.OrderBy(keySelector, descending);
}

Example

bool descending = (sortDirection = SortDirection.Descending);

PersonGridView.DataSource = persons.OrderBy(descending, p => p.Age, p => p.Name, p => p.Gender).ToList();

Author: Adam Weigert

Submitted on: 3 mrt. 2008

Language: C#

Type: System.Collections.Generic.IEnumerable<T>

Views: 12236