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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: 7595