Question

I have a List that I’m converting to a byte[] like so:

List<int> integerList = new List<int>();

integerList.Add(1);
integerList.Add(2);
integerList.Add(3);

byte[] bytes = integerList.SelectMany(BitConverter.GetBytes).ToArray();

How do I convert this back to a List?

Answer 1

One of the many ways to do it (a LINQ one):

var originalList = Enumerable.Range(0, bytes.Length / 4)
                             .Select(i => BitConverter.ToInt32(bytes, i * 4))
                             .ToList();

Minor update:

You can also write a handy generic version of this (just in case you’ll need to work with other types):

static List<T> ToListOf<T>(byte[] array, Func<byte[], int, T> bitConverter)
{
    var size = Marshal.SizeOf(typeof(T));
    return Enumerable.Range(0, array.Length / size)
                     .Select(i => bitConverter(array, i * size))
                     .ToList();
}

Usage:

var originalList = ToListOf<int>(bytes, BitConverter.ToInt32);