Basic Funda of XML,XSD,XSLT

Suppose this is ur XML. Person.xml

<Persons xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<Person>
<FirstName id="1">Kavita</FirstName>
<LastName>Khandhadia</LastName>
</Person>
<Person>
<FirstName id="2">Nishant</FirstName>
<LastName>Khandhadia</LastName>
</Person>
</Persons>

Now it may be possible that u want your XML to be in some proper format.. as XML is nothing but a
NODED string.. so you might want to validate your XML for following reasons

1 Wether it is in proper format or not
2 The node hierarchy is OK,or
3 If the data-types are correct in the XML

Now to validate an XML you must have something against which u can validate it..
We call it Schema file, which has normally XSD extensions.. there are other types of schema..but lets not get in to them right now..

Now for above example there can be an XSD file like this.

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified">
<xs:element name="Persons">
<xs:complexType>
<xs:sequence>
<xs:element maxOccurs="unbounded" ref="Person"/>
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:element name="Person">
<xs:complexType>
<xs:sequence>
<xs:element ref="FirstName"/>
<xs:element ref="LastName"/>
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:element name="FirstName">
<xs:complexType>
<xs:simpleContent>
<xs:extension base="xs:NCName">
<xs:attribute name="id" use="required" type="xs:integer"/>
</xs:extension>
</xs:simpleContent>
</xs:complexType>
</xs:element>
<xs:element name="LastName" type="xs:NCName"/>
</xs:schema>



Basically the above XSD/Schema will define that the XML should have root element as Persons and it has to have child element named Person and so on.


Now you have to tell your XML that which XSD to be used.. For this you have to add this attribute to your XML file like this -

<Persons xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="file:///C:/Documents%20and%20Settings/kavita.ACTLDOMAIN/Desktop/test/persons.xsd">

Now there are again ways to apply validations .. either using .net code behind or using some third party tool..

The code behind in C#.net to validate XML against XSD is as following.

public void ValidateXMLXSD()
{
string sFileName = Server.MapPath("person.xml");
XmlTextReader oTr = new XmlTextReader(sFileName);
XmlValidatingReader oVr = new XmlValidatingReader(oTr);

oVr.ValidationType = ValidationType.Schema;

oVr.ValidationEventHandler += new ValidationEventHandler(this.ValidationEvent);

while (oVr.Read())
{
if (oVr.NodeType == XmlNodeType.Text)
{
// lstXml.Items.Add(oVr.Value);
}
}

}

private void ValidationEvent(object s, ValidationEventArgs args)
{
Response.Write(args.Message.ToString());
//THe error messages will be print on screen.
}



Now lets come to XSLT...

Well it is one amazing way to transform one XML to another XML.
Suppose now in some case.. instead of above person.xml.. u want customer.xml which
takes data from person.xml but has totally different structure ..may be like this.


<?xml version='1.0' ?>
<Cusotmers>
<Customer>Kavita</Customer>
<Customer>Nishant</Customer>
</Cusotmers>


Following XSLT gives me output as above XML.

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

<xsl:template match="/">
<Cusotmers>
<xsl:for-each select="Persons/Person">
<Customer><xsl:value-of select="FirstName"/></Customer>
</xsl:for-each>
</Cusotmers>
</xsl:template>

</xsl:stylesheet>

Now again to transform the XML..and use XSLT the c#.net code behind is like this

XslTransform xslt = new XslTransform();
xslt.Load("file:///D:/Kavita/person.xslt");
//here sort.xslt shuid be the name of ur xslt file..please update the path also.
XPathDocument xpath = new XPathDocument("person.xml");
//here unSortXml is ur input XML.
Stream Streamdata = new FileStream(MapPath("Out.xml"), FileMode.Create, FileAccess.ReadWrite);
xslt.Transform(xpath, null, Streamdata, null);


FYI, u can write different types of transformation on single XML.