public int AddPostInfo(postInfo pi)
 {
     HelperSearch h = new HelperSearch();
     try
     {
         if (h.checkUniqPost(pi.postName) == 1)
         {
             db.postInfos.InsertOnSubmit(pi);
             db.SubmitChanges();
             return pi.postCode;
         }
         else
         {
             return 0;
         }
     }
     catch (Exception error)
     {
         return -1;
     }
 }