Split C# collection into equal parts, maintaining sort

Question

I am trying to split a collection into multiple collections while maintaining a sort I have on the collection. I have tried using the following extension method, but it breaks

Answer 1

A slightly more clean LINQ approach, for this rather old question:

public static IEnumerable> Partition(this IEnumerable source, int n)
{
    var count = source.Count();

    return source.Select((x, i) => new { value = x, index = i })
        .GroupBy(x => x.index / (int)Math.Ceiling(count / (double)n))
        .Select(x => x.Select(z => z.value));
}