How to convert List element to byte[] array?

Question

C++ / C#

First I declare a list : Then I fill it with data:
List<string> K = new List<string>();

K.Add("FirstString");
K.Add("SecondString");
K.Add("ThirdString");

When I want to take the i-th element of a list and convert it to an array of bytes,

byte[] tmp = K[i].SelectMany(s => Encoding.Default.GetBytes(s)).ToArray();

VS throws an error:
The most appropriate overloaded method for "System.Text.Encoding.GetBytes(char[])" has multiple invalid arguments

Answer 1

Have you tried s.ToCharArray()?

Answer 2

You are calling SelectMany on string. Therefore s is of type char. But GetBytes is expecting a string.
For some reason it seems to me that you wanted to write like this:
byte[] tmp = K.SelectMany(s => Encoding.Default.GetBytes(s)).ToArray();
Or so
byte[] tmp = Encoding.Default.GetBytes(K[i]);