protected void btnUpdate_Click(object sender, EventArgs e) { bool isValid = true; foreach (GridViewRow row in grvOrderDetails.Rows) { TextBox txtQty = (TextBox)row.FindControl("txtQty"); if (!objBAL.CheckIsValidNumber(txtQty.Text)) { isValid = false; } } if (isValid) { Dictionary <string, int> shoppingCartList = new Dictionary <string, int>(); foreach (GridViewRow row in grvOrderDetails.Rows) { shoppingCartList.Add(((HiddenField)row.FindControl("hdnProductID")).Value, Convert.ToInt32(((TextBox)row.FindControl("txtQty")).Text)); } string shoppingCartString = objBAL.UpdateShoppingCart(shoppingCartList); Session["ShoppingCart"] = shoppingCartString; FillCart(); } }