Using XmlReader.ReadElementContentAs (VB) : XmlReader « XML « ASP.NET Tutorial






<%@ Page Language="VB" AutoEventWireup="false" CodeFile="Default.aspx.vb" Inherits="_Default" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>Untitled Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
    
    </div>
    </form>
</body>
</html>

File: Default.aspx.vb

Imports System.IO
Imports System.Xml
Imports System.Xml.Schema

Partial Class _Default
    Inherits System.Web.UI.Page

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) _
           Handles Me.Load
        Dim bookcount As Integer = 0
        Dim booktotal As Decimal = 0
        Dim settings As New XmlReaderSettings()

        Dim nt As New NameTable()
        Dim book As Object = nt.Add("book")
        Dim price As Object = nt.Add("price")
        settings.NameTable = nt

        Dim booksSchemaFile As String = Path.Combine(Request.PhysicalApplicationPath, "Data.xsd")

        settings.Schemas.Add(Nothing, XmlReader.Create(booksSchemaFile))
        settings.ValidationType = ValidationType.Schema
        settings.ValidationFlags = XmlSchemaValidationFlags.ReportValidationWarnings

        AddHandler settings.ValidationEventHandler, _
        AddressOf settings_ValidationEventHandler

        settings.IgnoreWhitespace = True
        settings.IgnoreComments = True

        Dim booksFile As String = _
            Path.Combine(Request.PhysicalApplicationPath, "Data.xml")
        Using reader As XmlReader = XmlReader.Create(booksFile, settings)
            While (reader.Read())
                If (reader.NodeType = XmlNodeType.Element _
                    And book.Equals(reader.LocalName)) Then
                    'A subtle, but significant change!
                    bookcount += 1
                End If
                If (reader.NodeType = XmlNodeType.Element And price.Equals(reader.LocalName)) Then
                    booktotal += CType(reader.ReadElementContentAsObject(), Decimal)
                End If

            End While
        End Using
        Response.Write(String.Format("Found {0} books that total {1:C}!", _
                bookcount, booktotal))
    End Sub

    Sub settings_ValidationEventHandler(ByVal sender As Object, _
            ByVal e As System.Xml.Schema.ValidationEventArgs)
        Response.Write(e.Message)
    End Sub

End Class

File: Data.xml

<?xml version='1.0'?>
<bookstore xmlns="http://example.books.com"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <book genre="A" 
          publicationdate="1981" 
          ISBN="1-11111-11-0">
        <title>title 1</title>
        <author>
            <first-name>A</first-name>
            <last-name>B</last-name>
        </author>
        <price>8</price>
    </book>
    <book genre="B" 
          publicationdate="1999" 
          ISBN="0-222-22222-2">
        <title>title 2</title>
        <author>
            <first-name>C</first-name>
            <last-name>D</last-name>
        </author>
        <price>11.99</price>
    </book>
</bookstore>

File: Data.xsd
<?xml version="1.0" encoding="utf-8"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:tns="http://example.books.com" xmlns="http://example.books.com" targetNamespace="http://example.books.com" elementFormDefault="qualified">
  <xsd:element name="bookstore" type="bookstoreType" />
  <xsd:complexType name="bookstoreType">
    <xsd:sequence maxOccurs="unbounded">
      <xsd:element name="book" type="bookType" />
    </xsd:sequence>
  </xsd:complexType>
  <xsd:complexType name="bookType">
    <xsd:sequence>
      <xsd:element name="title" type="xsd:string" />
      <xsd:element name="author" type="authorName" />
      <xsd:element name="price" type="xsd:decimal" />
    </xsd:sequence>
    <xsd:attribute name="genre" type="xsd:string" />
    <xsd:attribute name="publicationdate" type="xsd:string" />
    <xsd:attribute name="ISBN" type="xsd:string" />
  </xsd:complexType>
  <xsd:complexType name="authorName">
    <xsd:sequence>
      <xsd:element name="first-name" type="xsd:string" />
      <xsd:element name="last-name" type="xsd:string" />
    </xsd:sequence>
  </xsd:complexType>
</xsd:schema>








25.13.XmlReader
25.13.1.Processing XML with an XmlReader (C#)
25.13.2.Processing XML with an XmlReader (VB)
25.13.3.Using XmlReader.ReadElementContentAs (C#)
25.13.4.Using XmlReader.ReadElementContentAs (VB)
25.13.5.Optimizing XmlReader with a NameTable (C#)
25.13.6.Optimizing XmlReader with a NameTable (VB)
25.13.7.Validating XML with an XmlReader against an XML Schema (C#)
25.13.8.Validating XML with an XmlReader against an XML Schema (VB)