public string AddAttr(string attrname, string description, string categoryID, int type, string operateid)
 {
     var attrid = Guid.NewGuid().ToString().ToLower();
     var dal = new ProductsDAL();
     if (dal.AddAttr(attrid, attrname, description, categoryID, type, operateid))
     {
         CacheAttrs.Add(new ProductAttr()
         {
             AttrID = attrid,
             AttrName = attrname,
             Description = description,
             CategoryID = categoryID,
             ClientID = "",
             CreateTime = DateTime.Now,
             CreateUserID = operateid,
             Status = 1,
             AttrValues = new List<AttrValue>()
         });
         return attrid;
     }
     return string.Empty;
 }