小数总价

Question

错误在此代码中。很久以前，当我试图解决有关小数和整数的问题时，我得到了同样的错误。我怎么能解决这个问题？

protected void btnPlaceOrder_Click(object sender, EventArgs e)
    {
        string productids = string.Empty;
        DataTable dt;
        if (Session["MyCart"] != null)
        {
            dt = (DataTable)Session["MyCart"];

            decimal totalPrice, totalProducts;
            bool totalPriceConversionResult = decimal.TryParse(txtTotalPrice.Text, out totalPrice), totalProductsConversionResult = decimal.TryParse(txtTotalProducts.Text, out totalProducts);


            ShoppingCart k = new ShoppingCart()
            {
                CustomerName = txtCustomerName.Text,
                CustomerEmailID = txtCustomerEmailID.Text,
                CustomerAddress = txtCustomerAddress.Text,
                CustomerPhoneNo = txtCustomerPhoneNo.Text,
                TotalProducts = totalProductsConversionResult ? totalProducts : 0,
                TotalPrice = totalPriceConversionResult ? totalPrice : 0,
                ProductList = productids,
                PaymentMethod = rblPaymentMethod.SelectedItem.Text

            };
            DataTable dtResult = k.SaveCustomerDetails();

            for (int i = 0; i < dt.Rows.Count; i++) // loop on how many products are added by the user
            {
                ShoppingCart SaveProducts = new ShoppingCart()
                {
                    CustomerID = Convert.ToInt32(dtResult.Rows[0][0]),
                    ProductID = Convert.ToInt32(dt.Rows[i]["ProductID"]),
                    TotalProducts = Convert.ToInt32(dt.Rows[i]["ProductQuantity"]),
                };
                SaveProducts.SaveCustomerProducts();
            }

            Session.Clear();
            GetMyCart();

            lblTransactionNo.Text = "Your Transaction Number: " + dtResult.Rows[0][0];

            pnlOrderPlaceSuccessfully.Visible = true;
            pnlCheckOut.Visible = false;
            pnlCategories.Visible = false;
            pnlMyCart.Visible = false;
            pnlEmptyCart.Visible = false;
            pnlProducts.Visible = false;

            SendOrderPlacedAlert(txtCustomerName.Text, txtCustomerEmailID.Text, Convert.ToString(dtResult.Rows[0][0]));

            txtCustomerAddress.Text = string.Empty;
            txtCustomerEmailID.Text = string.Empty;
            txtCustomerName.Text = string.Empty;
            txtCustomerPhoneNo.Text = string.Empty;
            txtTotalPrice.Text = "0";
            txtTotalProducts.Text = "0";
        }
    }

错误是位置0没有行。 - ShoppingCart SaveProducts = new ShoppingCart（）

Answer 1

试试这段代码：

private void UpdateTotalBill()
{
    decimal vat = 0;
    decimal TotalPrice = 0;
    long TotalProducts = 0;
    foreach (DataListItem item in dlCartProducts.Items)
    {
        Label PriceLabel = item.FindControl("lblPrice") as Label; // get price 
        TextBox ProductQuantity = item.FindControl("txtProductQuantity") as TextBox; // get quantity

        Int64 priceLabel, productQuantity;
        bool conversionResult = Int64.TryParse(PriceLabel.Text, out priceLabel);
        if(!conversionResult) continue;
        conversionResult = Int64.TryParse(ProductQuantity.Text, out productQuantity);
        if(!conversionResult) continue;
        decimal ProductPrice = priceLabel * productQuantity; //computation fro product price. price * quantity
        vat = (TotalPrice + ProductPrice) * 0.12M; // computation for vat
        vat = Math.Round(vat, 2);
        TotalPrice = TotalPrice + ProductPrice;
        TotalProducts = TotalProducts + productQuantity;
    }
    Label1.Text =Convert.ToString(vat);
    txtTotalPrice.Text = Convert.ToString(TotalPrice + 40.0M + vat); // add vat + 40 delivery charge to total price
    txtTotalProducts.Text = Convert.ToString(TotalProducts);
}

Int64结构具有TryParse方法，如果解析失败将返回false。 希望这会有所帮助。

[编辑]

将TryParse参数转换为数字类型时，请尝试使用string方法。它更安全。但是在执行更多代码之前，应始终检查返回值。如果TryParse方法的返回值为false，则应停止执行代码并通知用户错误。

[编辑2]

更改此代码：

ShoppingCart k = new ShoppingCart()
{
    CustomerName = txtCustomerName.Text,
    CustomerEmailID = txtCustomerEmailID.Text,
    CustomerAddress = txtCustomerAddress.Text,
    CustomerPhoneNo = txtCustomerPhoneNo.Text,
    TotalProducts = Convert.ToInt32(txtTotalProducts.Text),
    TotalPrice = Convert.ToInt32(txtTotalPrice.Text),
    ProductList = productids,
    PaymentMethod = rblPaymentMethod.SelectedItem.Text

};

到以下代码：

decimal totalPrice, totalProducts;
bool totalPriceConversionResult = decimal.TryParse(txtTotalPrice.Text, out totalPrice), totalProductsConversionResult = decimal.TryParse(txtTotalProducts.Text, out totalProducts);


ShoppingCart k = new ShoppingCart()
{
    CustomerName = txtCustomerName.Text,
    CustomerEmailID = txtCustomerEmailID.Text,
    CustomerAddress = txtCustomerAddress.Text,
    CustomerPhoneNo = txtCustomerPhoneNo.Text,
    TotalProducts = totalProductsConversionResult ? totalProducts : 0,
    TotalPrice = totalPriceConversionResult ? totalPrice : 0,
    ProductList = productids,
    PaymentMethod = rblPaymentMethod.SelectedItem.Text

};