VB.Net/XML/XML Tree

Use Tree to Display XML document

       
" *************************************************************
" * (C) Copyright 2003 by Deitel & Associates, Inc.           *
" *     and Prentice Hall.                                    *
" * All Rights Reserved.                                      *
" *                                                           *
" * DISCLAIMER: The authors and publisher of this book have   *
" * used their best efforts in preparing the book. These      *
" * efforts include the development, research, and testing of *
" * the theories and programs to determine their              *
" * effectiveness. The authors and publisher make no warranty *
" * of any kind, expressed or implied, with regard to these   *
" * programs or to the documentation contained in these books.*
" * The authors and publisher shall not be liable in any event*
" * for incidental or consequential damages in connection     *
" * with, or arising out of, the furnishing, performance, or  *
" * use of these programs.                                    *
" *************************************************************
       
Imports System.Xml
Imports System.Windows.Forms
Imports System.CodeDom.rupiler
Public Class MainClass
   Shared Sub Main()
       Dim form1 As Form = New FrmXmlDom()
       Application.Run(form1)
   End Sub " Main
End Class
 
Public Class FrmXmlDom
   Inherits Form
   " TextBox and TreeView for displaying data
   Friend WithEvents txtConsole As TextBox
   Friend WithEvents treXml As TreeView
   " Buttons for building, printing and reseting DOM tree
   Friend WithEvents cmdBuild As Button
   Friend WithEvents cmdPrint As Button
   Friend WithEvents cmdReset As Button
   Private source As XmlDocument " reference to "XML document"
   " reference copy of source"s "XML document"
   Private copy As XmlDocument
   Private tree As TreeNode " TreeNode reference
   Public Sub New()
      MyBase.New()
      " This call is required by the Windows Form Designer.
      InitializeComponent()
      " Add any initialization after the 
      " InitializeComponent() call
      " create XmlDocument and load letter.xml
      source = New XmlDocument()
      source.Load("ExampleCode.xml")
      " initialize references to Nothing
      copy = Nothing
      tree = Nothing
   End Sub " New
#Region " Windows Form Designer generated code "
   "Form overrides dispose to clean up the component list.
   Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
      If disposing Then
         If Not (components Is Nothing) Then
            components.Dispose()
         End If
      End If
      MyBase.Dispose(disposing)
   End Sub
   "Required by the Windows Form Designer
   Private components As System.ruponentModel.Container
   "NOTE: The following procedure is required by the Windows Form Designer
   "It can be modified using the Windows Form Designer.  
   "Do not modify it using the code editor.
   <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
      Me.treXml = New System.Windows.Forms.TreeView()
      Me.cmdBuild = New System.Windows.Forms.Button()
      Me.txtConsole = New System.Windows.Forms.TextBox()
      Me.cmdPrint = New System.Windows.Forms.Button()
      Me.cmdReset = New System.Windows.Forms.Button()
      Me.SuspendLayout()
      "
      "treXml
      "
      Me.treXml.ImageIndex = -1
      Me.treXml.Location = New System.Drawing.Point(8, 40)
      Me.treXml.Name = "treXml"
      Me.treXml.SelectedImageIndex = -1
      Me.treXml.Size = New System.Drawing.Size(344, 192)
      Me.treXml.TabIndex = 3
      "
      "cmdBuild
      "
      Me.cmdBuild.Font = New System.Drawing.Font("Microsoft Sans Serif", 9.75!, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
      Me.cmdBuild.Location = New System.Drawing.Point(8, 8)
      Me.cmdBuild.Name = "cmdBuild"
      Me.cmdBuild.Size = New System.Drawing.Size(104, 23)
      Me.cmdBuild.TabIndex = 0
      Me.cmdBuild.Text = "Build"
      "
      "txtConsole
      "
      Me.txtConsole.Location = New System.Drawing.Point(8, 240)
      Me.txtConsole.Multiline = True
      Me.txtConsole.Name = "txtConsole"
      Me.txtConsole.ScrollBars = System.Windows.Forms.ScrollBars.Vertical
      Me.txtConsole.Size = New System.Drawing.Size(344, 96)
      Me.txtConsole.TabIndex = 4
      Me.txtConsole.Text = ""
      "
      "cmdPrint
      "
      Me.cmdPrint.Font = New System.Drawing.Font("Microsoft Sans Serif", 9.75!, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
      Me.cmdPrint.Location = New System.Drawing.Point(128, 8)
      Me.cmdPrint.Name = "cmdPrint"
      Me.cmdPrint.Size = New System.Drawing.Size(104, 23)
      Me.cmdPrint.TabIndex = 1
      Me.cmdPrint.Text = "Print"
      "
      "cmdReset
      "
      Me.cmdReset.Font = New System.Drawing.Font("Microsoft Sans Serif", 9.75!, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
      Me.cmdReset.Location = New System.Drawing.Point(248, 8)
      Me.cmdReset.Name = "cmdReset"
      Me.cmdReset.Size = New System.Drawing.Size(104, 23)
      Me.cmdReset.TabIndex = 2
      Me.cmdReset.Text = "Reset"
      "
      "FrmXmlDom
      "
      Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
      Me.ClientSize = New System.Drawing.Size(360, 341)
      Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.txtConsole, Me.treXml, Me.cmdReset, Me.cmdPrint, Me.cmdBuild})
      Me.Name = "FrmXmlDom"
      Me.Text = "Xml Dom"
      Me.ResumeLayout(False)
   End Sub
#End Region
   Private Sub cmdBuild_Click(ByVal sender As System.Object, _
      ByVal e As System.EventArgs) Handles cmdBuild.Click
      If Not copy Is Nothing Then
         Return " document already exists
      End If
      copy = New XmlDocument()
      tree = New TreeNode()
      tree.Text = source.Name " assigns #root
      treXml.Nodes.Add(tree)
      BuildTree(source, copy, tree)
   End Sub 
   Private Sub cmdPrint_Click(ByVal sender As System.Object, _
      ByVal e As System.EventArgs) Handles cmdPrint.Click
      If copy Is Nothing Then
         Return
      End If
      Dim file As TempFileCollection = New TempFileCollection()
      file.AddExtension("xml", False)
      Dim filename As String() = New String(0) {}
      file.CopyTo(filename, 0)
      Dim writer As XmlTextWriter = _
        New XmlTextWriter(filename(0), _
        System.Text.Encoding.UTF8)
      copy.WriteTo(writer)
      writer.Close()
      Dim reader As XmlTextReader = _
         New XmlTextReader(filename(0))
      While reader.Read
         If reader.NodeType = XmlNodeType.EndElement Then
            txtConsole.Text &= "/"
         End If
         If reader.Name <> String.Empty Then
            txtConsole.Text &= reader.Name & vbCrLf
         End If
         If reader.Value <> String.Empty Then
            txtConsole.Text &= vbTab & reader.Value & vbCrLf
         End If
      End While
      reader.Close()
   End Sub 
   Private Sub cmdReset_Click(ByVal sender As System.Object, _
      ByVal e As System.EventArgs) Handles cmdReset.Click
      If Not tree Is Nothing Then
         treXml.Nodes.Remove(tree)
      End If
      treXml.Refresh() 
      copy = Nothing
      tree = Nothing
      txtConsole.Clear() 
   End Sub 
   Private Sub BuildTree(ByVal xmlSourceNode As XmlNode, _
      ByVal documentValue As XmlNode, _
      ByVal treeNode As TreeNode)
      Dim nodeReader As XmlNodeReader = _
         New XmlNodeReader(xmlSourceNode)
      Dim currentNode As XmlNode = Nothing
      Dim newNode As TreeNode = New TreeNode()
      Dim modifiedNodeType As XmlNodeType
      While nodeReader.Read
         modifiedNodeType = nodeReader.NodeType
         If modifiedNodeType = XmlNodeType.EndElement Then
            modifiedNodeType = XmlNodeType.Element
         End If
         currentNode = copy.CreateNode(modifiedNodeType, _
            nodeReader.Name, nodeReader.NamespaceURI)
         Select Case nodeReader.NodeType
         Case XmlNodeType.Text
               newNode.Text = nodeReader.Value
               treeNode.Nodes.Add(newNode)
               CType(currentNode, XmlText).AppendData _
                  (nodeReader.Value)
               documentValue.AppendChild(currentNode)
            Case XmlNodeType.EndElement
               documentValue = documentValue.ParentNode
               treeNode = treeNode.Parent
            Case XmlNodeType.Element
               If Not nodeReader.IsEmptyElement Then
                  newNode.Text = nodeReader.Name
                  treeNode.Nodes.Add(newNode)
                  treeNode = newNode
                  documentValue.AppendChild(currentNode)
                  documentValue = documentValue.LastChild
               Else 
                  newNode.Text = nodeReader.NodeType.ToString
                  treeNode.Nodes.Add(newNode)
                  documentValue.AppendChild(currentNode)
               End If
            Case Else 
               newNode.Text = nodeReader.NodeType.ToString
               treeNode.Nodes.Add(newNode)
               documentValue.AppendChild(currentNode)
         End Select
         newNode = New TreeNode()
      End While
      treXml.ExpandAll()
      treXml.Refresh()
   End Sub
End Class