using (SqlConnection connection = new SqlConnection(connectionString))
         {
            String updateStr = @"UPDATE ";
            using (SqlCommand cmd = new SqlCommand(updateStr, connection))
            {
               cmd.Parameters.AddWithValue("@iid", iid);
               cmd.Parameters.AddWithValue("@cid", cid);
               connection.Open();
               cmd.ExecuteNonQuery();
            }
         }
      }

         using (SqlConnection connection = new SqlConnection(connectionString))
         {
            String updateStr = @"UPDATE ";
            using (SqlCommand cmd = new SqlCommand(updateStr, connection))
            {
               connection.Open();
                // так реально сделать??
               foreach(Item it in Items)
               {
                   cmd.Parameters.AddWithValue("@iid", it.iid);
                   cmd.Parameters.AddWithValue("@cid", it.cid);
                   cmd.ExecuteNonQuery();
               }

            }
         }
      }