Reading XML in to a List(Of Object)

Michael Brown

I am having a hard time reading a XML file in to a List(Of Object) in vb.net Any help would be appreciated.

The problem occurs when the deserialization happens. I get the following error

System.InvalidOperationException: 'There is an error in XML document (2, 2).'

Inner Exception InvalidOperationException: was not expected.

XML

<?xml version="1.0" encoding="UTF-8"?>
<CRecord>
  <CD>
    <TITLE>Empire Burlesque</TITLE>
    <ARTIST>Bob Dylan</ARTIST>
    <COUNTRY>USA</COUNTRY>
    <COMPANY>Columbia</COMPANY>
    <PRICE>10.90</PRICE>
    <YEAR>1985</YEAR>
  </CD>
  <CD>
    <TITLE>Hide your heart</TITLE>
    <ARTIST>Bonnie Tyler</ARTIST>
    <COUNTRY>UK</COUNTRY>
    <COMPANY>CBS Records</COMPANY>
    <PRICE>9.90</PRICE>
    <YEAR>1988</YEAR>
  </CD>
  <CD>
    <TITLE>Greatest Hits</TITLE>
    <ARTIST>Dolly Parton</ARTIST>
    <COUNTRY>USA</COUNTRY>
    <COMPANY>RCA</COMPANY>
    <PRICE>9.90</PRICE>
    <YEAR>1982</YEAR>
  </CD>
  <CD>
    <TITLE>Still got the blues</TITLE>
    <ARTIST>Gary Moore</ARTIST>
    <COUNTRY>UK</COUNTRY>
    <COMPANY>Virgin records</COMPANY>
    <PRICE>10.20</PRICE>
    <YEAR>1990</YEAR>
  </CD>
  <CD>
    <TITLE>Eros</TITLE>
    <ARTIST>Eros Ramazzotti</ARTIST>
    <COUNTRY>EU</COUNTRY>
    <COMPANY>BMG</COMPANY>
    <PRICE>9.90</PRICE>
    <YEAR>1997</YEAR>
  </CD>
  <CD>
    <TITLE>One night only</TITLE>
    <ARTIST>Bee Gees</ARTIST>
    <COUNTRY>UK</COUNTRY>
    <COMPANY>Polydor</COMPANY>
    <PRICE>10.90</PRICE>
    <YEAR>1998</YEAR>
  </CD>
  <CD>
    <TITLE>Sylvias Mother</TITLE>
    <ARTIST>Dr.Hook</ARTIST>
    <COUNTRY>UK</COUNTRY>
    <COMPANY>CBS</COMPANY>
    <PRICE>8.10</PRICE>
    <YEAR>1973</YEAR>
  </CD>
  <CD>
    <TITLE>Maggie May</TITLE>
    <ARTIST>Rod Stewart</ARTIST>
    <COUNTRY>UK</COUNTRY>
    <COMPANY>Pickwick</COMPANY>
    <PRICE>8.50</PRICE>
    <YEAR>1990</YEAR>
  </CD>
  <CD>
    <TITLE>Romanza</TITLE>
    <ARTIST>Andrea Bocelli</ARTIST>
    <COUNTRY>EU</COUNTRY>
    <COMPANY>Polydor</COMPANY>
    <PRICE>10.80</PRICE>
    <YEAR>1996</YEAR>
  </CD>
  <CD>
    <TITLE>When a man loves a woman</TITLE>
    <ARTIST>Percy Sledge</ARTIST>
    <COUNTRY>USA</COUNTRY>
    <COMPANY>Atlantic</COMPANY>
    <PRICE>8.70</PRICE>
    <YEAR>1987</YEAR>
  </CD>
  <CD>
    <TITLE>Black angel</TITLE>
    <ARTIST>Savage Rose</ARTIST>
    <COUNTRY>EU</COUNTRY>
    <COMPANY>Mega</COMPANY>
    <PRICE>10.90</PRICE>
    <YEAR>1995</YEAR>
  </CD>
  <CD>
    <TITLE>1999 Grammy Nominees</TITLE>
    <ARTIST>Many</ARTIST>
    <COUNTRY>USA</COUNTRY>
    <COMPANY>Grammy</COMPANY>
    <PRICE>10.20</PRICE>
    <YEAR>1999</YEAR>
  </CD>
  <CD>
    <TITLE>For the good times</TITLE>
    <ARTIST>Kenny Rogers</ARTIST>
    <COUNTRY>UK</COUNTRY>
    <COMPANY>Mucik Master</COMPANY>
    <PRICE>8.70</PRICE>
    <YEAR>1995</YEAR>
  </CD>
  <CD>
    <TITLE>Big Willie style</TITLE>
    <ARTIST>Will Smith</ARTIST>
    <COUNTRY>USA</COUNTRY>
    <COMPANY>Columbia</COMPANY>
    <PRICE>9.90</PRICE>
    <YEAR>1997</YEAR>
  </CD>
  <CD>
    <TITLE>Tupelo Honey</TITLE>
    <ARTIST>Van Morrison</ARTIST>
    <COUNTRY>UK</COUNTRY>
    <COMPANY>Polydor</COMPANY>
    <PRICE>8.20</PRICE>
    <YEAR>1971</YEAR>
  </CD>
  <CD>
    <TITLE>Soulsville</TITLE>
    <ARTIST>Jorn Hoel</ARTIST>
    <COUNTRY>Norway</COUNTRY>
    <COMPANY>WEA</COMPANY>
    <PRICE>7.90</PRICE>
    <YEAR>1996</YEAR>
  </CD>
  <CD>
    <TITLE>The very best of</TITLE>
    <ARTIST>Cat Stevens</ARTIST>
    <COUNTRY>UK</COUNTRY>
    <COMPANY>Island</COMPANY>
    <PRICE>8.90</PRICE>
    <YEAR>1990</YEAR>
  </CD>
  <CD>
    <TITLE>Stop</TITLE>
    <ARTIST>Sam Brown</ARTIST>
    <COUNTRY>UK</COUNTRY>
    <COMPANY>A and M</COMPANY>
    <PRICE>8.90</PRICE>
    <YEAR>1988</YEAR>
  </CD>
  <CD>
    <TITLE>Bridge of Spies</TITLE>
    <ARTIST>T'Pau</ARTIST>
    <COUNTRY>UK</COUNTRY>
    <COMPANY>Siren</COMPANY>
    <PRICE>7.90</PRICE>
    <YEAR>1987</YEAR>
  </CD>
  <CD>
    <TITLE>Private Dancer</TITLE>
    <ARTIST>Tina Turner</ARTIST>
    <COUNTRY>UK</COUNTRY>
    <COMPANY>Capitol</COMPANY>
    <PRICE>8.90</PRICE>
    <YEAR>1983</YEAR>
  </CD>
  <CD>
    <TITLE>Midt om natten</TITLE>
    <ARTIST>Kim Larsen</ARTIST>
    <COUNTRY>EU</COUNTRY>
    <COMPANY>Medley</COMPANY>
    <PRICE>7.80</PRICE>
    <YEAR>1983</YEAR>
  </CD>
  <CD>
    <TITLE>Pavarotti Gala Concert</TITLE>
    <ARTIST>Luciano Pavarotti</ARTIST>
    <COUNTRY>UK</COUNTRY>
    <COMPANY>DECCA</COMPANY>
    <PRICE>9.90</PRICE>
    <YEAR>1991</YEAR>
  </CD>
  <CD>
    <TITLE>The dock of the bay</TITLE>
    <ARTIST>Otis Redding</ARTIST>
    <COUNTRY>USA</COUNTRY>
    <COMPANY>Stax Records</COMPANY>
    <PRICE>7.90</PRICE>
    <YEAR>1968</YEAR>
  </CD>
  <CD>
    <TITLE>Picture book</TITLE>
    <ARTIST>Simply Red</ARTIST>
    <COUNTRY>EU</COUNTRY>
    <COMPANY>Elektra</COMPANY>
    <PRICE>7.20</PRICE>
    <YEAR>1985</YEAR>
  </CD>
  <CD>
    <TITLE>Red</TITLE>
    <ARTIST>The Communards</ARTIST>
    <COUNTRY>UK</COUNTRY>
    <COMPANY>London</COMPANY>
    <PRICE>7.80</PRICE>
    <YEAR>1987</YEAR>
  </CD>
  <CD>
    <TITLE>Unchain my heart</TITLE>
    <ARTIST>Joe Cocker</ARTIST>
    <COUNTRY>USA</COUNTRY>
    <COMPANY>EMI</COMPANY>
    <PRICE>8.20</PRICE>
    <YEAR>1987</YEAR>
  </CD>
</CRecord>

Model Class

<Serializable()>
Public Class CRecord
    Public Property Title() As String
    Public Property Artist() As String
    Public Property Country() As String
    Public Property Price() As Double
    Public Property Year() As Integer
End Class

Code

'' Member Variable
Private m_Records As New List(Of CRecord)

Private Sub btnImport_Click(sender As Object, e As EventArgs) Handles btnImport.Click

    '' Create an instance of the XmlSerializer.
    Dim serializer As New XmlSerializer(GetType(List(Of CRecord)))
    Dim temp As List(Of CRecord)
    '' Declare an object variable of the type to be deserialized.
    Dim record As CRecord = Nothing

    Using reader As New FileStream(sXmlPath, FileMode.Open)
        '' Call the Deserialize method to restore the object's state.
        m_Records = CType(serializer.Deserialize(reader), List(Of CRecord))
    End Using
End Sub
JayV

I worked on the assumption that you cannot change any part of the Xml structure, and would prefer to change your own VB.Net code

I renamed your class CRecord to CD as it better represents what you are loading, and the XmlDeserialization process will match the Xml name to the Class name.

Also, I added the attribute <XmlElement("..."> to each of the properties as the Xml Element name is all upper case and the VB.Net property is not. You can choose not to add this attribute, but then you will need to change the property names to be all upper case to match the Xml.

The final bit of code needed was telling the XmlSerializer class what to use for the root node:

New XmlRootAttribute("CRecord")

<Serializable()>
Public Class CD
    <XmlElement("TITLE")>
    Public Property Title() As String

    <XmlElement("ARTIST")>
    Public Property Artist() As String

    <XmlElement("COUNTRY")>
    Public Property Country() As String

    <XmlElement("PRICE")>
    Public Property Price() As Double

    <XmlElement("YEAR")>
    Public Property Year() As Integer
End Class

<TestMethod()>
Public Sub Test_XmlDeserialize()

    Dim m_Records As List(Of CD)

    Dim sXmlPath = "D:\Sample.xml"

    '' Create an instance of the XmlSerializer.
    Dim serializer As New XmlSerializer(GetType(List(Of CD)), New XmlRootAttribute("CRecord"))

    Using reader As New FileStream(sXmlPath, FileMode.Open)
        '' Call the Deserialize method to restore the object's state.
        m_Records = CType(serializer.Deserialize(reader), List(Of CD))
    End Using

With these updates, you should be able to Deserialze the Xml as required.

enter image description here

Collected from the Internet

Please contact [email protected] to delete if infringement.

edited at
0

Comments

0 comments
Login to comment

Related