XML VB.Net

Option Explicit
Option Strict
Imports System
Imports System.IO
Imports System.Xml
Public Class Sample
    Private Shared filename As String = "sampledata.xml"
    Public Shared Sub Main()
        Dim writer As XmlTextWriter = Nothing
        writer = New XmlTextWriter(filename, Nothing)
        writer.Formatting = Formatting.Indented
        writer.WriteStartDocument()
        Dim PItext As String = "type='text/xsl' href='book.xsl'"
        writer.WriteProcessingInstruction("xml-stylesheet", PItext)
        writer.WriteDocType("book", Nothing, Nothing, "")
        writer.WriteComment("sample XML")
        writer.WriteStartElement("book")
        writer.WriteAttributeString("genre", "Programming")
        writer.WriteAttributeString("ISBN", "1-111111-014")
        writer.WriteElementString("title", "C#")
        writer.WriteStartElement("style")
        writer.WriteEntityRef("h")
        writer.WriteEndElement()
        writer.WriteElementString("price", "9.9")
        writer.WriteCData("Prices 15% off!!")
        writer.WriteEndElement()
        writer.WriteEndDocument()
        writer.Flush()
        writer.Close()
        Dim doc As New XmlDocument()
        doc.PreserveWhitespace = True
        doc.Load(filename)
        Console.Write(doc.InnerXml)
    End Sub 'Main 
End Class 'Sample