public OAUsers UpdateStateByUserName(string where)
        {
            try
            {
                StringBuilder strSql = new StringBuilder();
                strSql.Append("update OAUser set");
                strSql.Append(" state=1");
                if (where.Trim() != null)
                {
                    strSql.Append(" where username=@username");
                }
                SqlParameter[] para = 
                                 { 
                                  new SqlParameter("@username",SqlDbType.NVarChar,50)
                                  };
                OAUsers use = new OAUsers();
                para[0].Value = use.Username;
                int res = DbHelperSQL.ExecuteSql(strSql.ToString(), para);
                if (res > 0)
                {
                    return use;
                }
                else
                {
                    return null;
                }
            }
            catch (Exception ex)
            {                
                throw new Exception(ex.ToString());
            }
        }