Trim()

 /**//// <summary>
        /// 通过User Name获取user id的table
        /// 如果有非法的user则提示用户修改并返回null
        /// </summary>
        /// <param name="userNameList">user names  比如：Sammy Song;Lili Zhang;</param>
        /// <returns>user table</returns>
        public DataTable GetUserIDsForAdmin(string userNameList)
        {
                //对参数字符串处理，比如';;;;;;Sammy Song;;;;;;Lili Zhang;;;;;;' 这样的字符串，先Trim掉两边所有的分号，再把中间多个分号用正则替换成一个
            userNameList = userNameList.Trim(';');
            userNameList = Regex.Replace(userNameList, ";+", ";");
            string[] userCheckString = userNameList.Split(';');
            List<string> userCheckList = new List<string>();            
            userCheckList.Add(userCheckString[0].ToLower());

            //去除重复的名字
            for (int i = 0; i < userCheckString.Length; i++)
            {
                if (!userCheckList.Contains(userCheckString[i].ToLower()) && userCheckString[i].Trim() != "")
                {
                    userCheckList.Add(userCheckString[i].ToLower());
                }
            }

            //获取user table
            BenQ.Public.Web.WSC.Entity.Wscuser entityCheckUser = new BenQ.Public.Web.WSC.Entity.Wscuser();
            entityCheckUser.QueryMode = true;
            entityCheckUser.Account.In(userCheckString);
            entityCheckUser.Active += true;
            DataTable userTable = entityCheckUser.Query(new QString[] { entityCheckUser.Userid, entityCheckUser.Account },
                false, -1).Tables[0];

            //返回的行数小于非重复user name的个数,则有非法的user name,提示用户出错
            if (userTable.Rows.Count != userCheckList.Count)
            {
                for (int j = 0; j < userTable.Rows.Count; j++)
                {
                    if (userCheckList.Contains(userTable.Rows[j]["account"].ToString().ToLower()))
                    {
                        userCheckList.Remove(userTable.Rows[j]["account"].ToString().ToLower());
                    }
                }
                string invalidUser = "";
                for (int k = 0; k < userCheckList.Count; k++)
                {
                    invalidUser += "," + userCheckList[k];
                }
                invalidUser = invalidUser.TrimStart(',');
                this.showMessageInfo(this.getMessage("WM10005").Replace("%User%", invalidUser));
                return null;
            }
            //没有非法用户,
            return userTable;
        }