Reading from XMLText Reader and adding to List of Classes

Question

I have an XML file hosted on a website that I need to read using XMLText Reader. As I am reading, I need to add the items from the XML document as I am reading them to the list of classes. I'm not sure what parameters I should be passing through and the foreach section.

transList is my List and Transaction is my class. They have been globally defined at the top for future use for XML Serializer to write to an XML file that I have already written.

XML File with multiple transactions

<portfolio>
<transaction>
<ticker>GOOG</ticker>
<action>buy</action>
<date>20071116</date>
<shares>44</shares>
</transaction>


public class Transaction
{
    public string ticker { get; set; }
    public string action { get; set; }
    public string date { get; set; }
    public int numShares { get; set; }
    public double price { get; set; }
}

List<Transaction> transList = new List<Transaction>();


void readPortfolio(string filename)
    {
        XmlTextReader reader = new XmlTextReader(filename);
        reader.WhitespaceHandling = WhitespaceHandling.None;

        foreach(var transaction in reader) //for each reader node equal to “transaction” do:
         {
                TransList.add(Transaction tr = new Transaction(ticker, action, date, number of shares))

         }

Welcome to Stack Overflow! FYI, you should not use `new XmlTextReader()` or `new XmlTextWriter()`. They have been deprecated since .NET 2.0. Use `XmlReader.Create()` or `XmlWriter.Create()` instead. — John Saunders, Feb 18 '13 at 19:26
Yes, welcome to the site. Remember to accept an answer using the 'tick' if it answers your question. — Neo, Feb 19 '13 at 09:35

Neo · Answer 1 · 2013-02-18T18:54:46.507

Try this:

public class Transaction
{
    public string Ticker { get; set; }
    public string Action { get; set; }
    public string Date { get; set; }
    public int NumShares { get; set; }
    public double Price { get; set; }
}

void ReadPortfolio(string filename)
{
    if (File.Exists(filename))
    {
        var transList = new List<Transaction>();

        foreach (XElement transaction in XDocument.Load(filename).Descendants("transaction"))
        {
            XElement ticker = transaction.Element("ticker");
            XElement action = transaction.Element("action");
            XElement date = transaction.Element("date");
            XElement shares = transaction.Element("shares");
            XElement price = transaction.Element("price");

            transList.Add(new Transaction
                {
                    Ticker = ticker != null ? ticker.Value : string.Empty,
                    Action = action != null ? action.Value : string.Empty,
                    Date = date != null ? date.Value : string.Empty,
                    NumShares = shares != null ? int.Parse(shares.Value) : default(int),
                    Price = price != null ? double.Parse(price.Value) : default(double)
                });
        }
    }
}

This method handles cases where there may be missing elements and I've rewritten your code a little to be more compliant with convention. It also checks the file exists.

This looks like a financial application, so I should also point out that you would be better using decimal rather than double. decimal is considered the appropriate way to handle money due to floating point precision issues with double.

score 0 · Answer 2 · answered Feb 18 '13 at 18:24

Here is how to do it with an XDocument... Just uncomment the line with the filename (and comment the line which parses the constant!) and pass a filename in.

class Program
{
    static void Main(string[] args)
    {
        var test = new AnotherXmlTest();
        test.readPortfolio("filename");

        //Put a break on this line and instect object 'test'
        Console.ReadLine();
    }
}

public class AnotherXmlTest
{
    public const string xml = @"<portfolio><transaction><ticker>GOOG</ticker><action>buy</action><date>20071116</date><shares>44</shares></transaction></portfolio>";


    public class Transaction
    {
        public string ticker { get; set; }
        public string action { get; set; }
        public string date { get; set; }
        public int numShares { get; set; }
        public double price { get; set; }
    }

    List<Transaction> transList = new List<Transaction>();


    public void readPortfolio(string filename)
    {
        //Use this instead!
        //XmlTextReader reader = new XmlTextReader(filename);
        //XDocument xDoc = XDocument.Load(reader);
        XDocument xDoc = XDocument.Parse(xml);

        transList.AddRange(from transaction in xDoc.Descendants("transaction")
                           select new Transaction
                           {
                               ticker = transaction.Element("ticker").Value,
                               action = transaction.Element("action").Value,
                               date = transaction.Element("date").Value,
                               numShares = Convert.ToInt32(transaction.Element("shares").Value)
                               // No price?? 
                           });


    }
}

Of course, if you dont need to use XMlTextReader, you can just pass uri directly into XDocument.Load(fileName) instead... but code provided the way it is as you said you have to use an XmlTextReader... — Jay, Feb 18 '13 at 18:30

score 0 · Answer 3 · edited May 23 '17 at 11:49

If you want to get nifty, an alternative method to the other one I provided is using LINQ:

public class Transaction
{
    public string Ticker { get; set; }
    public string Action { get; set; }
    public string Date { get; set; }
    public int NumShares { get; set; }
    public double Price { get; set; }
}

void ReadPortfolio(string filename)
{
    if (File.Exists(filename))
    {
        var transList = new List<Transaction>();
        transList.AddRange(from transaction in XDocument.Load(filename).Descendants("transaction")
                           let ticker = transaction.Element("ticker")
                           let action = transaction.Element("action")
                           let date = transaction.Element("date")
                           let shares = transaction.Element("shares")
                           let price = transaction.Element("price")
                           select new Transaction
                               {
                                   Ticker = ticker != null ? ticker.Value : string.Empty,
                                   Action = action != null ? action.Value : string.Empty,
                                   Date = date != null ? date.Value : string.Empty,
                                   NumShares = shares != null ? int.Parse(shares.Value) : default(int),
                                   Price = price != null ? double.Parse(price.Value) : default(double)
                               });
    }
}

Reading from XMLText Reader and adding to List of Classes

3 Answers3