We can easily convert a comma-separated string into a List in C# using String.Split() method.

In the below code snippet, String.Split() method splits a comma-separated string into substrings based on the characters in an array, then you can convert the arrays into a list as shown below. You have to add the reference System.Linq for the method ToList().

using System;
using System.Linq;
using System.Collections.Generic;

namespace ConvertCommSepStringToList
{
    class Program
    {
        static void Main()
        {
            // Comma-seperated String
            string colorStr = "Red,Blue,White,Pink,Yellow";

            // Split a string into substrings based on the ","
            List<string> colors = colorStr.Split(',').ToList();

            // Display the element
            foreach (string color in colors)
                Console.WriteLine(color);            
            Console.ReadKey();
        }
    }
}

Output:

Red
Blue
White
Pink
Yellow