Serializing .NET Objects to XML: An Example in C#

1. .NET and XML

2. From Objects to XML using System; using System.Xml.Serialization; using System.IO; namespace XmlTest { public class Node { private double stockPrice; private double optionPrice; public double StockPrice { get { return stockPrice; } set { stockPrice = value; } }

3. public double OptionPrice { get { return optionPrice; } set { optionPrice = value; } } } public class XmlMain { static void Main(string[] args) { Node n = new Node(); n.StockPrice = 100.0; n.OptionPrice = 3.00;

4. XmlSerializer xs = new XmlSerializer(typeof(Node)); Stream s = File.OpenWrite("Node.xml"); xs.Serialize(s,n); s.Close(); } } }

5. Node.xml <?xml version="1.0"?> <Node xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <StockPrice>100</StockPrice> <OptionPrice>3</OptionPrice> </Node>

6. Controlling Serialization using System; using System.Xml.Serialization; using System.IO; namespace XmlTest { [XmlRoot("TreeNode")] public class Node { private double stockPrice; private double optionPrice;

7. [XmlElement("sp")] public double StockPrice { get { return stockPrice; } set { stockPrice = value; } } [XmlElement("op")] public double OptionPrice { get { return optionPrice; } set { optionPrice = value; } } }

8. public class XmlMain { static void Main(string[] args) { Node n = new Node(); n.StockPrice = 100.0; n.OptionPrice = 3.00; XmlSerializer xs = new XmlSerializer(typeof(Node)); Stream s = File.OpenWrite("Node.xml"); xs.Serialize(s,n); s.Close(); } } }

9. Node.xml <?xml version="1.0"?> <TreeNode xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <sp>100</sp> <op>3</op> </TreeNode>e>3</OptionPrice> </Node>

10. XMLSerializer in Web Services // NodeService.cs using System; using System.Web.Services; namespace XMLWebService { public class NodeService : System.Web.Services.WebService { [WebMethod] public Node getNode() { return new Node(100.0,3.0); } }

11. public class Node { private double stockPrice; private double optionPrice; public double StockPrice { get { return stockPrice; } set { stockPrice = value; } } public double OptionPrice { get { return optionPrice; } set { optionPrice = value; } } public Node(double sp, double op) { StockPrice = sp; OptionPrice = op; }

12. // required for web service public Node() { StockPrice = 0.0; OptionPrice = 0.0; } } public class XmlMain { public static void Main(string[] args) { NodeService ns = new NodeService(); Node n = ns.getNode(); Console.WriteLine(n.OptionPrice); } } }

13. ACoolNodeService.asmx <%@ WebService Language="C#“ Class="XMLWebService.NodeService" %> • Place in a directory above bin • In the bin directory place the compiled .dll file NodeService.dll • Run IIS and choose default web site • Action/New/Virtual Directory and set an alias to the directory containing the .asmx file (above bin)

14. Response in a browser <?xml version="1.0" encoding="utf-8"?> <Node xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://tempuri.org/"> <StockPrice>100</StockPrice> <OptionPrice>3</OptionPrice> </Node>

15. Client Side • Get the wsdl with a browser • Run wsdl.exe • Compile output of wsdl to a .dll • Compile client and reference the .dll • Run the client

16. using System; public class ClientMain { public static void Main() { NodeService ns = new NodeService(); Node n = ns.getNode(); Console.WriteLine(n.OptionPrice + " " + n.StockPrice); } } ..\46-690\examples\XMLSerialization\webservices\client>ClientMain 3 100

17. Basic XML Processing // XmlTextReader Demo using System.Xml; using System.IO; using System; class XmlDemo { static void Main() { String xml = "<student><score>100</score></student>"; XmlTextReader xmlTextReader = new XmlTextReader( new StringReader(xml));

18. // build an empty DOM tree XmlDocument doc = new XmlDocument(); // load the tree from a string doc.Load(xmlTextReader); // get the root of the xml XmlElement root = doc.DocumentElement; // write its value Console.WriteLine(root.Name); // point at the child element XmlElement score = (XmlElement)root.FirstChild;

19. // write the element name Console.WriteLine(score.Name); // point to its child XmlText value = (XmlText) score.FirstChild; // look at the contents of the text node Console.WriteLine(value.Value); } } XmlDemo.exe student score 100

20. Reading a file FixedFloatSwap.xml <?xml version="1.0" encoding="UTF-8"?> <FixedFloatSwap> <Bank>Bank of London</Bank> <Notional currency = "pounds">100</Notional> <Fixed_Rate>5</Fixed_Rate> <NumYears>3</NumYears> <NumPayments>6</NumPayments> </FixedFloatSwap>

21. // Reading any XML file using System.Xml; using System.IO; using System; class XmlDemo { static void Main() { XmlTextReader reader = new XmlTextReader("FixedFloatSwap.xml");

22. while (reader.Read()) { switch (reader.NodeType) { case XmlNodeType.XmlDeclaration: Console.WriteLine("XmlDeclaration"); break; case XmlNodeType.ProcessingInstruction: Console.WriteLine("ProcessingInstruction"); break; case XmlNodeType.DocumentType: Console.WriteLine("DocumentType"); break; case XmlNodeType.Comment: Console.WriteLine("Comment"); break;

23. case XmlNodeType.Element: Console.WriteLine("Element"); if (reader.HasAttributes) Console.WriteLine("Attributes found"); break; case XmlNodeType.Text: Console.WriteLine("Text"); break; case XmlNodeType.Whitespace: Console.WriteLine("Whitespace"); break; } } } }

24. D:\McCarthy\www\46-690\examples\XmlProcessing>XmlURLDemo XmlDeclaration Whitespace Element Whitespace Element Text Whitespace Element Attributes found Text Whitespace Element Text Whitespace Element Text Whitespace Element Text Whitespace

25. Reading from the net • Suppose the FixedFloatSwap.xml is found At http://localhost/FpML/FixedFloatSwap.xml • To do that, simply place the FixedFloatSwap.xml file in a directory and create a virtual directory in IIS. This directory would have the alias FpML.

26. // Reading any XML file from a URL using System.Xml; using System.IO; using System; class XmlDemo { static void Main() { XmlTextReader reader = new XmlTextReader("http://localhost/FpML/FixedFloatSwap.xml"); while (reader.Read()) { switch (reader.NodeType) { case XmlNodeType.XmlDeclaration: Console.WriteLine("XmlDeclaration"); break;

27. case XmlNodeType.ProcessingInstruction: Console.WriteLine("ProcessingInstruction"); break; case XmlNodeType.DocumentType: Console.WriteLine("DocumentType"); break; case XmlNodeType.Comment: Console.WriteLine("Comment"); break; case XmlNodeType.Element: Console.WriteLine("Element"); if (reader.HasAttributes) Console.WriteLine("Attributes found"); break;

28. case XmlNodeType.Text: Console.WriteLine("Text"); break; case XmlNodeType.Whitespace: Console.WriteLine("Whitespace"); break; } } } }

29. D:\McCarthy\www\46-690\examples\XmlProcessing>XmlURLDemo XmlDeclaration Whitespace Element Whitespace Element Text Whitespace Element Attributes found Text Whitespace Element Text Whitespace Element Text Whitespace Element Text Whitespace