add two strings to two dimensional list

Question

i want to add in two set of strings to one list

i receive error that i cant use add

        List<List<String>> lastmodified1 = new List<List<String>>();
        lastmodified1.Add(new List<String>());

        foreach (string filenamelocal in files)
        {
            string name = Path.GetFileName(filenamelocal);
            lastmodified1[0][1].Add(Convert.ToString(filenamelocal));
            lastmodified1[0][0].Add(Convert.ToString(File.GetLastAccessTime(filenamelocal)));

        }

Answer 1

you target the list with the first index

        lastmodified1[0].Add(Convert.ToString(filenamelocal));
        lastmodified1[0].Add(Convert.ToString(File.GetLastAccessTime(filenamelocal)));

with the index [0] you are target the list, because the first List is implicit. so with

    lastmodified1[0].Add(Convert.ToString(filenamelocal)); //this is accessing to the List inside the First list

you are accesing to the second List inside from the first List. with the second index you're accessing to the value of the second list, in this case String, and you can get the method add because strings dont have

    lastmodified1[0][0] //this access to string value