Question

string[] lines3 = new string[100];
List<string> lines2 = new List<string>();
lines3 = Regex.Split(s1, @"\s*,\s*");

if (!lines2.Contains(lines3.ToString()))
{
    lines2.AddRange(lines3.Distinct().ToArray());
}

I have checked all the spaces etc but i still get duplicate values in my lines2 List

I have to remove my duplicate values here itself

Answer 1

Your this check:

if (!lines2.Contains(lines3.ToString()))

is invalid. You are checking if your lines2 contains System.String[] since lines3.ToString() will give you that. You need to check if item from lines3 exists in lines2 or not.

You can iterate each item in lines3 check if it exists in the lines2 and then add it. Something like.

foreach (string str in lines3)
{
    if (!lines2.Contains(str))
        lines2.Add(str);
}

Or if your lines2 is any empty list, then you can simply add the lines3 distinct values to the list like:

lines2.AddRange(lines3.Distinct());

then your lines2 will contain distinct values.