Question

This is not a question but instead is an example that might be useful to someone like me who wants to study how the VB.NET XmlDocument node hierarchy works.

The following subroutine recursively walks the XML document tree displaying elements and attributes as encountered…

Private Sub XmlDocumentWalker(XmlNode As XmlNode)

    If TypeOf XmlNode Is XmlComment Then

        MsgBox(XmlNode.Value, MsgBoxStyle.OkOnly, "XML Comment")

        If XmlNode.HasChildNodes Then XmlDocumentWalker(XmlNode.FirstChild)
        If Not IsNothing(XmlNode.NextSibling) Then XmlDocumentWalker(XmlNode.NextSibling)

    ElseIf TypeOf XmlNode Is XmlElement Then

        If XmlNode.HasChildNodes And (TypeOf XmlNode.FirstChild Is XmlText) Then

            MsgBox(XmlNode.Name & "=""" & XmlNode.FirstChild.Value & """", MsgBoxStyle.OkOnly, "XML Element")

        Else

            MsgBox(XmlNode.Name, MsgBoxStyle.OkOnly, "XML Element")

        End If

        If DirectCast(XmlNode, XmlElement).HasAttributes Then
            For Each XmlAttribute As XmlNode In DirectCast(XmlNode, XmlElement).Attributes

                MsgBox(XmlAttribute.Name & "=""" & XmlAttribute.Value & """", MsgBoxStyle.OkOnly, "XML Attribute")

            Next
        End If

        If XmlNode.HasChildNodes And Not (TypeOf XmlNode.FirstChild Is XmlText) Then XmlDocumentWalker(XmlNode.FirstChild)
        If Not IsNothing(XmlNode.NextSibling) Then XmlDocumentWalker(XmlNode.NextSibling)
    End If
End Sub

The following code is provided to illustrate actually loading an XML Document to be walked by the XMLDocumentWalker subroutine:

Private XmlDocument As XmlDocument

Private ValidationErrorCount As Integer

Public Sub Load()
    ValidationErrorCount = 0

    Try
        Dim XmlReader As XmlReader
        Dim XmlReaderSettings As New XmlReaderSettings()
        Dim ValidationEventHandler As New ValidationEventHandler(AddressOf XMLValidationErrorMessage)

        XmlReaderSettings.ValidationType = ValidationType.DTD
        XmlReaderSettings.DtdProcessing = DtdProcessing.Parse

        AddHandler XmlReaderSettings.ValidationEventHandler, ValidationEventHandler

        XmlReader = XmlReader.Create(FileName, XmlReaderSettings)

        XmlDocument = New XmlDocument()

        XmlDocument.Load(XmlReader)

        If 0 = ValidationErrorCount Then
            XmlDocumentWalker(XmlDocument)
        End If

    Catch Exception As Exception
        XmlDocument = Nothing
        MsgBox(Exception.Message, MsgBoxStyle.Information + MsgBoxStyle.OkOnly, "Configuration file load error")
    End Try
End Sub

Private Sub XMLValidationErrorMessage(ByVal sender As Object, ByVal args As ValidationEventArgs)
    If 0 = ValidationErrorCount Then
        MsgBox(ConfigurationResource, MsgBoxStyle.Information + MsgBoxStyle.OkOnly, "Configuration file invalid")
    End If

    MsgBox(args.Message, MsgBoxStyle.Information + MsgBoxStyle.OkOnly, "XML format error")

    ValidationErrorCount += 1
End Sub

Answer 1

Because this really isn’t a question – I’m tagging it as answered.