using System;

public class Program

{

    public static void Main()

    {

        var userName = @"ABC/Domain-name\Pinto";

        var prefix = userName.Substring(0, userName.IndexOf('/'));

        var user = userName.Substring(userName.LastIndexOf('\\'));

        Console.WriteLine(@"Prefix\User: " + prefix + user);

​

        Console.WriteLine("User Only: " + user.Substring(1));

​

        prefix = userName.Substring(0, userName.IndexOf('/')+1);

        user = userName.Substring(userName.LastIndexOf('\\')+1);

        Console.WriteLine(@"Prefix/User: " + prefix + user);

​

        Console.WriteLine("User Only: " + user);

    }

}