扩展ShoppingCartInfo对象以在Kentico CMS中添加新的税务类别

最初，我想添加到Kentico的内置税务类中。我想我可以通过从TaxClassInfo类继承并为ZIPCodeID定义一个新字段来实现这一点，然后覆盖TaxClassInfoProvider类的方法来添加ZIPCodeID作为计算税款的参数。

然而，税务类的类并没有按照我预期的方式建模，而且我真的无法理解税务类、购物车和所有其他相关电子商务类中所有数据的相关位置，因为我无法访问源代码。

因此，我只是创建了一个自定义TaxClassInfoProvider类，并根据Kentico的这次网络研讨会重写了GetTaxesInternal（）方法。

页面底部代码示例中的一个文件几乎已经构建好了：

using System;
using System.Web;
using System.Data;
using System.Collections.Generic;
using CMS.Ecommerce;
using CMS.SettingsProvider;
using CMS.SiteProvider;
using CMS.GlobalHelper;
/// <summary>
/// Sample tax class info provider. 
/// Can be registered either by replacing the TaxClassInfoProvider.ProviderObject (uncomment the line in SampleECommerceModule.cs) or through cms.extensibility section of the web.config
/// </summary>
public class CustomTaxClassInfoProvider : TaxClassInfoProvider
{
    #region "Example: Custom taxes calculation"
    /// <summary>
    /// Returns DataSet with all the taxes which should be applied to the shopping cart items.
    /// </summary>
    /// <param name="cart">Shopping cart</param>
    protected override DataSet GetTaxesInternal(ShoppingCartInfo cart)
    {
        DataSet ds = new DataSet();
        // Create an empty taxes table
        DataTable table = GetNewTaxesTable();
        // Build taxes table 
        // ------------------------
        // Please note:         
        // Taxes table is built manually for the purpose of this example, however you can build it from the response of a tax calculation service as well.
        // All the data which might be required for the calculation service is stored in the ShoppingCartInfo object, e.g.:
        // - use AddressInfoProvider.GetAddresInfo(cart.ShoppingCartBillingAddressID) to get billing address info
        // - use AddressInfoProvider.GetAddresInfo(cart.ShoppingCartShippingAddressID) to get shipping address info        
        // etc.
        // ------------------------
        foreach (ShoppingCartItemInfo item in cart.CartItems)
        {
            // Get SKU properties
            string skuNumber = item.SKU.SKUNumber.ToLowerCSafe();
            int skuId = item.SKUID;
            switch (skuNumber)
            {
                // Tax for product A (20%)
                case "a":
                    AddTaxRow(table, skuId, "Tax A", 20);
                    break;
                // Taxes for product B (11% and 10%)
                case "b":
                    AddTaxRow(table, skuId, "Tax B1", 11);
                    AddTaxRow(table, skuId, "Tax B2", 10);
                    break;
                // Zero tax for product C (0%)
                case "c":
                    break;
                // The same tax for all other products (5%)
                default:
                    AddTaxRow(table, skuId, "Tax C", 5);
                    break;
            }
        }
        // Return built dataset with the taxes
        ds.Tables.Add(table);
        return ds;
    }
    #region "Private methods"
    /// <summary>
    /// Creates an empty taxes table.
    /// </summary>    
    private DataTable GetNewTaxesTable()
    {
        DataTable table = new DataTable();
        // Add required columns
        table.Columns.Add("SKUID", typeof(int));
        table.Columns.Add("TaxClassDisplayName", typeof(string));
        table.Columns.Add("TaxValue", typeof(double));
        // Add optional columns
        //table.Columns.Add("TaxIsFlat", typeof(bool));
        //table.Columns.Add("TaxIsGlobal", typeof(bool));
        //table.Columns.Add("TaxClassZeroIfIDSupplied", typeof(bool));
        return table;
    }

    /// <summary>
    /// Creates tax row which holds the data of the tax which should be applied to the given SKU.
    /// </summary>
    /// <param name="taxTable">Tax table the row should be added to.</param>
    /// <param name="skuId">SKU ID</param>
    /// <param name="taxName">Tax name</param>
    /// <param name="taxValue">Tax value</param>
    /// <param name="taxIsFlat">Indicates if the tax value is flat or relative. By default it is false (= relative tax)</param>
    /// <param name="taxIsGlobal">Indicates if the tax value is in global main currency or in site main currency. By default it is false (= tax value is in site main currency).</param>    
    /// <param name="taxIsGlobal">Indicates if the tax is zero if customer's registration ID is supplied. By default it is false (= tax is not zero if customer's tax registration ID is supplied).</param>    
    private void AddTaxRow(DataTable taxTable, int skuId, string taxName, double taxValue, bool taxIsFlat, bool taxIsGlobal, bool zeroTaxIfIDSupplied)
    {
        DataRow row = taxTable.NewRow();
        // Set required columns
        row["SKUID"] = skuId;
        row["TaxClassDisplayName"] = taxName;
        row["TaxValue"] = taxValue;
        // Set optional columns
        //row["TaxIsFlat"] = taxIsFlat;
        //row["TaxIsGlobal"] = taxIsGlobal;
        //row["TaxClassZeroIfIDSupplied"] = taxIsGlobal;
        taxTable.Rows.Add(row);
    }

    /// <summary>
    /// Creates tax row which holds the data of the tax which should be applied to the given SKU.
    /// </summary>
    /// <param name="taxTable">Tax table the row should be added to.</param>
    /// <param name="skuId">SKU ID</param>
    /// <param name="taxName">Tax name</param>
    /// <param name="taxValue">Tax value</param>
    private void AddTaxRow(DataTable taxTable, int skuId, string taxName, double taxValue)
    {
        AddTaxRow(taxTable, skuId, taxName, taxValue, false, false, false);
    }
    #endregion
    #endregion
}

找到这个之后，我在SQL Server中创建了一个非常简单的3列表，其中包含ID、ZIP和TaxRate。

然后，我对上面的代码进行了一些修改，以使用地址信息提供商访问税率和当前客户的地址信息

AddressInfo customerAddress = AddressInfoProvider.GetAddressInfo(cart.ShoppingCartShippingAddressID);

之后，只需要用我的邮政编码税率填充一个数据集，然后将适当的税率传递给AddTaxRow（）方法。