/// <summary>
        /// 用户名是否重复
        /// </summary>
        /// <param name="userInfo">用户</param>
        /// <param name="fieldNames">字段名</param>
        /// <param name="fieldValues">字段值</param>
        /// <returns>已存在</returns>
        public bool Exists(UserInfo userInfo, string[] fieldNames, object[] fieldValues)
        {
            bool returnValue = false;

            var parameter = ParameterUtil.CreateWithLog(userInfo, MethodBase.GetCurrentMethod());

            ServiceUtil.ProcessRDIReadDb(userInfo, parameter, dbProvider =>
            {
                var userManager = new PiUserManager(dbProvider);
                returnValue     = userManager.Exists(fieldNames, fieldValues);
            });
            return(returnValue);
        }