C# - Substring problem

[Creelers]

Trying to shorten a string.

            string[] Files = Directory.GetFiles(path, "*.SAV");
            foreach (string s in Files)
            {
                s.Substring(30, 10);
                listView1.Items.Add(s);
            }

But it doesn't actually change the string at all for some reason, help?

 

[Creelers]

Ah right. Thanks mate.