C generates instances of random number lists that do not repeat

/// <summary>
        ///  Generates a random number list instance that does not repeat 
        /// </summary>
        /// <param name="count"> Do not repeat the count </param>
        /// <returns> Do not repeat the list of Numbers </returns>
        private static List<int> GetRandomList(int count)
        {
            List<int> list = new List<int>();
            int num = 0;
            Random rnd = new Random();
            for (int i = 0; i < count; i++)
            {
                do
                {
                    num = rnd.Next(010000, 1000000);
                } while (list.Contains(num));//                
                list.Add(num);
            }
            return list;
        }