C#- 泛型去除重复项

        //防止群发，出现重复通知，去除重复项
        private List<UserEmail> GetNotRepeatSentingEmail(List<UserEmail> LSentingEmail)
        {
            List<UserEmail> Result = new List<UserEmail>();
            Hashtable hash = new Hashtable();
            Result.Clear();
            hash.Clear();
            for (int i = 0; i < LSentingEmail.Count; i++)
            {
                if (!hash.ContainsKey(LSentingEmail[i].T_To) && !hash.ContainsValue(LSentingEmail[i].T_Subject))
                {
                    hash.Add(LSentingEmail[i].T_To, LSentingEmail[i].T_Subject);
                    Result.Add(LSentingEmail[i]);
                }
            }
            return Result;
        }