public void addItemWarehouse(Item_Warehouse iw)
        {
            using (SqlConnection con = new SqlConnection(connectionString))

            {
                SqlCommand cmd = new SqlCommand("Insert into Item_Warehouse values(@itemId,@warehouseId,@quantity,@orders)", con);

                cmd.Parameters.AddWithValue("@itemId", iw.itemId);
                cmd.Parameters.AddWithValue("@warehouseId", iw.warehouseId);
                cmd.Parameters.AddWithValue("@quantity", iw.quantity);
                cmd.Parameters.AddWithValue("@orders", iw.orders);

                con.Open();
                cmd.ExecuteNonQuery();
            }
        }
        public void updateItemWarehouse(Item_Warehouse iw)
        {
            using (SqlConnection con = new SqlConnection(connectionString))

            {
                SqlCommand cmd = new SqlCommand("Update Item_Warehouse SET quantity=@quantity Where(itemId=@itemId AND warehouseId=@warehouseId)", con);
                cmd.Parameters.AddWithValue("@quantity", iw.quantity);
                cmd.Parameters.AddWithValue("@itemId", iw.itemId);
                cmd.Parameters.AddWithValue("@warehouseId", iw.warehouseId);



                con.Open();
                cmd.ExecuteNonQuery();
            }
        }