using System.Linq;

namespace ConsoleApplication11    {
    class Program
    {
        string me_login_name;
        int me_pkey;

        public static void Main()
        {
            new Program().Run();
        }

        private void Run()
        {
            IQueryable<v2oneboxDataEntity> me_employees = null;

            var duplicate =
                from  loginId in me_employees
                where loginId.me_login_name == this.me_login_name
                        && loginId.me_pkey != this.me_pkey
                select loginId;

            var count = duplicate.Count();            
        }

        // Define other methods and classes here
        class v2oneboxDataEntity 
        {
            public string me_login_name { get; set; }
            public int me_pkey { get; set; }
        }
    }
}