Xml in .NET

The XML types are live in System.XML namespace

1. Import System.XML like

using System.XML // now we are ready to use xml in .net

2. we have two core abstract classes in XML.NET XmlReader and XmlWriter

XmlReader : Fast,read-only and Forward only cursor for processing xml documents
Xml Writer : Alows to produce xml documents with W3C's XML 1.0 + Namespaces Rcommendations

These two are inexpensive in memory cache which makes as alternatives to the classic DOM approach

How to Read XML Document in XML.NET ?
Reading xml document with XmlReader class , here is the example

public void ReadDocument(XmlReader reader)
{

while (reader.Read())
{
 // Points to the Current Node of the Xml Document
 String name = (reader.NodeType == XmlNodeType.Element ||
   reader.NodeType == XmlNodeType.EndElement) ?
   reader.NamespaceURI + "#" + reader.Name : reader.Name;
 Console.WriteLine(name);   
}
}

How to Write into XML Document in XML.NET

public void WriteDocument()
{
XmlWriter writer = new XmlTextWriter(Server.MapPath("test.xml"), null);
         writer.WriteStartDocument();
         writer.WriteComment("This is a sample comment");
         writer.WriteStartElement("Carworld");
         writer.WriteStartElement("name", "");
         writer.WriteString("Maruthi");
         writer.WriteEndElement();
         writer.WriteStartElement("name", "");
         writer.WriteString("Hyundai");
         writer.WriteEndElement();
         writer.WriteStartElement("name", "");
         writer.WriteString("Daewoo");
  writer.WriteEndElement();
        writer.WriteEndElement();


         writer.WriteEndDocument();

          writer.Close();

}

How to Read or write with XmlDocument ?

1. assaign the xml file to XmlDocument object with Load method
2. Start from the Root Element  and Display the XmlNode details
3.Check if that Node contains Child Nodes if so process them too ..

public void ReadXmlDocument()
{
string fname = "test.xml";
try
{
// Load the XML from file
XmlDocument myDoc = new XmlDocument();
myDoc.Load(Server.MapPath(fname));
// Process the supplied XML file
ProcessXmlFile(myDoc.DocumentElement);
      }
catch (Exception e)
 {
  Response.Write(ex.Message());
  }
 }

public void ProcessXmlFile(XmlNode node)
{
if (node != null)
Response.Write(" Node Name :: + "+node.Name +" --> Node Value :: "+node.Value+"<br>");
 if (node.HasChildNodes)
{
node = node.FirstChild;
while (node != null)
 {
    ProcessXmlFile(node);
    node = node.NextSibling;
 }
}

}

In the above example ... ProcessXmlFile() is a simple and recursive fuction to traverse in between xml node elements,

How to Process Xml Nodes with XmlNode.SelectNodes()?

if you know under which XmlNode your required element is .. then XmlNode.SelectNodes() will work fine ...

Here is a example of How XmlNode.SelectNodes() will work

public void ProcessDynamic()
{
XmlDocument doc = new XmlDocument();
doc.Load(Server.MapPath("test.xml"));
string str = "";
XmlNodeList list;
str = "/carworld/name";
list = doc.SelectNodes(str);
this.ddlcamp.Items.Clear();

ListItem li = new ListItem();

foreach (XmlNode xn in list)
{
  if ( xn.Value=="maruthi")
    li = new ListItem();
    li.Text = cn.Attributes["name"].Value;
    li.Value = cn.Attributes["name"].Value;
    this.ddlcamp.Items.Add(li);

  }
}
 }
Happy Coding :)