如何使用XDocument编写子元素

Question

我已经修改了这个问题，并包括到目前为止为这个问题编写的代码。下面是输出必须与VeriFone MX915支付终端兼容的示例。在这个特定的部分，我试图发送POS注册项目到显示。

<TRANSACTION>
    <FUNCTION_TYPE>LINE_ITEM</FUNCTION_TYPE>
    <COMMAND>ADD</COMMAND>
    <COUNTER>1</COUNTER>
    <MAC> … </MAC>
    <MAC_LABEL>REG2</MAC_LABEL>
    <RUNNING_SUB_TOTAL>7.00</RUNNING_SUB_TOTAL>
    <RUNNING_TRANS_AMOUNT>7.42</RUNNING_TRANS_AMOUNT>
    <RUNNING_TAX_AMOUNT>0.42</RUNNING_TAX_AMOUNT>
    <LINE_ITEMS>
        <MERCHANDISE>
            <UNIT_PRICE>5.00</UNIT_PRICE>
            <DESCRIPTION>#1 Combo Meal</DESCRIPTION>
            <LINE_ITEM_ID>1695155651</LINE_ITEM_ID>
            <EXTENDED_PRICE>5.00</EXTENDED_PRICE>
            <QUANTITY>1</QUANTITY>
        </MERCHANDISE>
    </LINE_ITEMS>
</TRANSACTION>

VeriFone提供的SDK提供了一些与设备通信所需的方法。因此，下面的代码具有编写的方法调用和类级变量，但这些变量未包含在以下示例中：

/// <summary>
        /// Send 1 or more items to the Verifone display.  Include subtotal, tax and total
 /// </summary>
 /// <param name="nSubTotal">Subtotal of transaction</param>
 /// <param name="nTax">Current Tax of transaction</param>
 /// <param name="nTotal">Total of transaction</param>
 /// <param name="UPC">Item Code</param>
 /// <param name="ShortDescription">Small description</param>
 /// <param name="nItemAmount">Item Amt</param>
 /// <param name="nQty">Quantity</param>
 /// <param name="nExtendedAmount">Quantity X Item Amt</param>
 /// <returns></returns>
        public bool AddLineItem(double nSubTotal, double nTax, double nTotal, Int32 nItemID, string UPC, string ShortDescription, double nItemAmount, Int32 nQty, double nExtendedAmount)
        {

            // get counter and calculate Mac
            var nextCounter = (++counter).ToString();
            var mac = PrintMacAsBase64(macKey, nextCounter);

            // build request
            var request = new XDocument();
            using (var writer = request.CreateWriter())
            {
                //populate the elements
                writer.WriteStartDocument();
                writer.WriteStartElement("TRANSACTION");
                writer.WriteElementString("FUNCTION_TYPE", "LINE_ITEM");
                writer.WriteElementString("COMMAND", "ADD");
                writer.WriteElementString("MAC_LABEL", macLabel);
                writer.WriteElementString("COUNTER", nextCounter);
                writer.WriteElementString("MAC", mac);
                writer.WriteElementString("RUNNING_SUB_TOTAL",nSubTotal.ToString("c"));
                writer.WriteElementString("RUNNING_TAX_AMOUNT",nTax.ToString("c"));
                writer.WriteElementString("RUNNING_TRANS_AMOUNT",nTotal.ToString("c"));

                //HERE IS WHERE I NEED TO WRITE THE CHILD ELEMENT(s):  

                //example below of what they or it would look like 
                //(collection of merchandise elements under Line_items)
                //I know this example will have only one item because of parameters

                /*
                <LINE_ITEMS>
                    <MERCHANDISE>
                        <LINE_ITEM_ID>10</LINE_ITEM_ID>
                        <DESCRIPTION>This is a dummy</DESCRIPTION>
                        <UNIT_PRICE>1.00</UNIT_PRICE>
                        <QUANTITY>1</QUANTITY>
                        <EXTENDED_PRICE>1.00</EXTENDED_PRICE>
                    </MERCHANDISE>
                </LINE_ITEMS>
                */

                writer.WriteEndElement();
                writer.WriteEndDocument();
            }

            // transmit to Point Solution and interrogate the response
            var responseXml = Send(address, port, request);


            //DO SOMETHING HERE WITH THE RESPONSE
            // validate that the RESULT_CODE came back a SUCCESS
            if ("-1" != responseXml.Element("RESPONSE").Element("RESULT_CODE").Value)
            {
                throw new Exception(responseXml.Element("RESPONSE").Element("RESULT_TEXT").Value ?? "unknown error");
            }
            return true;


        }

如果有人能帮助我理解如何填充子元素，就像我在代码中放置注释时所指出的那样，我将非常感谢。

感谢主持人要求提供更多有关这方面的信息。

Answer 1

我认为使用XmlSerializer是个好主意，也许下面的代码可以帮助您。XmlSerializer比XmlWriter更直观地生成Xml。：)

using System;
using System.Collections.Generic;
using System.Xml.Serialization;

class Program
{
    static void Main(string[] args)
    {
        Transaction transaction = new Transaction();
        transaction.Function_Type = "LINE_ITEM";
        transaction.LineItems = new List<Merchandise>();
        transaction.LineItems.Add(new Merchandise() { UnitPrice = "5.00" });

        //Create our own namespaces for the output
        XmlSerializerNamespaces ns = new XmlSerializerNamespaces();

        //Add an empty namespace and empty value
        ns.Add("", "");

        using (XmlWriter writer = XmlWriter.Create(Console.Out, new XmlWriterSettings { OmitXmlDeclaration = true }))
        {
            new XmlSerializer(typeof(Transaction)).Serialize(writer, transaction, ns);
        }

        Console.Read();
    }
}

[XmlRoot("TRANSACTION")]
public class Transaction
{
    [XmlElement("FUNCTION_TYPE")]
    public string Function_Type { get; set; }

    [XmlArray("LINE_ITEMS")]
    [XmlArrayItem("MERCHANDISE")]
    public List<Merchandise> LineItems { get; set; }
}

[XmlRoot("MERCHANDISE")]
public class Merchandise
{
    [XmlElement("UNIT_PRICE")]
    public string UnitPrice { get; set; }
}

结果：

​

Answer 2

你可以用XmlDocument

    XmlDocument xmlDoc = new XmlDocument();

    XmlNode rootNode = xmlDoc.CreateElement("RootNode");
    xmlDoc.AppendChild(rootNode);

    foreach (Class objItem in classArray)
    {


        XmlNode firstNode= xmlDoc.CreateElement("First");
        XmlNode second= xmlDoc.CreateElement("Second");
        second.InnerText = objItem .Text;
        firstNode.AppendChild(second);

        rootNode.AppendChild(firstNode);
    }
    StringWriter stringWriter = new StringWriter();
    XmlTextWriter textWriter = new XmlTextWriter(stringWriter);
    xmlDoc.WriteTo(textWriter);