Question

I want to make a method that can accept both List<byte> and array of bytes as argument (as Resharper suggested):

public static UInt16 GetSourceAddress(IEnumerable<byte> packet)
{
    return BitConverter.ToUInt16(new[] {packet[4], packet[5]}, 0);
}

Bute I get the follwing compilation error:

Cannot apply indexing with [] to an expression of type 'System.Collections.Generic.IEnumerable<byte>'

I know I can just go ahead with two overloads with List and byte[], but what does this problem indicates? How to resolve it?

Answer 1

If you want random access, use IList<T> instead:

public static UInt16 GetSourceAddress(IList<byte> packet)

Both List<byte> and byte[] implement IList<byte>, and it has an indexer.