LayoutVisitor Class

Defines the basic functionality that should be implemented by visitors that traverse the document layout tree.

Namespace: DevExpress.XtraRichEdit.API.Layout

Assembly: DevExpress.RichEdit.v24.2.Core.dll

NuGet Package: DevExpress.RichEdit.Core

Declaration

C#

public abstract class LayoutVisitor

VB.NET

Public MustInherit Class LayoutVisitor

Remarks

Refer to the Traversing Layout Tree section for details.

Example

Form1.cs

class TreeViewCollector : LayoutVisitor
{
    readonly TreeView view;
    Dictionary<LayoutElement, TreeNode> dictionary;
    RichEditControl richEdit;

    public TreeViewCollector(TreeView view, RichEditControl richEdit)
    {
        this.view = view;
        this.dictionary = new Dictionary<LayoutElement, TreeNode>();
        this.richEdit = richEdit;
    }

    public TreeView View { get { return view; } }
    public Dictionary<LayoutElement, TreeNode> Dictionary { get { return dictionary; } }
    public RichEditControl RichEdit { get { return richEdit; } }

    protected override void VisitPage(LayoutPage page)
    {
        TreeNode item = new TreeNode();
        item.Text = String.Format("{0} #{1}", "Page", page.Index + 1); ;
        Dictionary.Add(page, item);
        base.VisitPage(page);
        View.Nodes.Add(item);
    }
    protected override void VisitHeader(LayoutHeader header)
    {
        AddTreeNode(header, ContentDisplayAction.ScrollTo);
        base.VisitHeader(header);
    }
    protected override void VisitFooter(LayoutFooter footer)
    {
        AddTreeNode(footer, ContentDisplayAction.ScrollTo);
        base.VisitFooter(footer);
    }
    protected override void VisitPageArea(LayoutPageArea pageArea)
    {
        AddTreeNode(pageArea, ContentDisplayAction.Select);
        base.VisitPageArea(pageArea);
    }
    protected override void VisitBookmarkEndBox(BookmarkBox bookmarkEndBox)
    {
        AddTreeNode(bookmarkEndBox, ContentDisplayAction.Select);
        base.VisitBookmarkEndBox(bookmarkEndBox);
    }
    protected override void VisitBookmarkStartBox(BookmarkBox bookmarkStartBox)
    {
        AddTreeNode(bookmarkStartBox, ContentDisplayAction.Select);
        base.VisitBookmarkStartBox(bookmarkStartBox);
    }
    protected override void VisitColumn(LayoutColumn column)
    {
        AddTreeNode(column, ContentDisplayAction.Select);
        base.VisitColumn(column);
    }
    protected override void VisitColumnBreakBox(PlainTextBox columnBreakBox)
    {
        AddTreeNode(columnBreakBox, ContentDisplayAction.Select);
        base.VisitColumnBreakBox(columnBreakBox);
    }
    protected override void VisitComment(LayoutComment comment)
    {
        AddTreeNode(comment, ContentDisplayAction.ScrollTo);
        base.VisitComment(comment);
    }
    protected override void VisitCommentEndBox(CommentBox commentEndBox)
    {
        AddTreeNode(commentEndBox, ContentDisplayAction.Select);
        base.VisitCommentEndBox(commentEndBox);
    }
    protected override void VisitCommentHighlightAreaBox(CommentHighlightAreaBox commentHighlightAreaBox)
    {
        AddTreeNode(commentHighlightAreaBox, ContentDisplayAction.Select);
        base.VisitCommentHighlightAreaBox(commentHighlightAreaBox);
    }
    protected override void VisitCommentStartBox(CommentBox commentStartBox)
    {
        AddTreeNode(commentStartBox, ContentDisplayAction.Select);
        base.VisitCommentStartBox(commentStartBox);
    }
    protected override void VisitFieldHighlightAreaBox(FieldHighlightAreaBox fieldHighlightAreaBox)
    {
        AddTreeNode(fieldHighlightAreaBox, ContentDisplayAction.Select);
        base.VisitFieldHighlightAreaBox(fieldHighlightAreaBox);
    }
    protected override void VisitFloatingObjectAnchorBox(FloatingObjectAnchorBox floatingObjectAnchorBox)
    {
        AddTreeNode(floatingObjectAnchorBox, ContentDisplayAction.Select);
        base.VisitFloatingObjectAnchorBox(floatingObjectAnchorBox);
    }
    protected override void VisitFloatingPicture(LayoutFloatingPicture floatingPicture)
    {
        AddTreeNode(floatingPicture, ContentDisplayAction.ScrollTo);
        base.VisitFloatingPicture(floatingPicture);
    }
    protected override void VisitHiddenTextUnderlineBox(HiddenTextUnderlineBox hiddenTextUnderlineBox)
    {
        AddTreeNode(hiddenTextUnderlineBox, ContentDisplayAction.Select);
        base.VisitHiddenTextUnderlineBox(hiddenTextUnderlineBox);
    }
    protected override void VisitHighlightAreaBox(HighlightAreaBox highlightAreaBox)
    {
        AddTreeNode(highlightAreaBox, ContentDisplayAction.Select);
        base.VisitHighlightAreaBox(highlightAreaBox);
    }
    protected override void VisitHyphenBox(PlainTextBox hyphen)
    {
        AddTreeNode(hyphen, ContentDisplayAction.Select);
        base.VisitHyphenBox(hyphen);
    }
    protected override void VisitInlinePictureBox(InlinePictureBox inlinePictureBox)
    {
        AddTreeNode(inlinePictureBox, ContentDisplayAction.Select);
        base.VisitInlinePictureBox(inlinePictureBox);
    }
    protected override void VisitLineBreakBox(PlainTextBox lineBreakBox)
    {
        AddTreeNode(lineBreakBox, ContentDisplayAction.Select);
        base.VisitLineBreakBox(lineBreakBox);
    }
    protected override void VisitLineNumberBox(LineNumberBox lineNumberBox)
    {
        AddTreeNode(lineNumberBox, ContentDisplayAction.Select);
        base.VisitLineNumberBox(lineNumberBox);
    }
    protected override void VisitNumberingListMarkBox(NumberingListMarkBox numberingListMarkBox)
    {
        AddTreeNode(numberingListMarkBox, ContentDisplayAction.Select);
        base.VisitNumberingListMarkBox(numberingListMarkBox);
    }
    protected override void VisitNumberingListWithSeparatorBox(NumberingListWithSeparatorBox numberingListWithSeparatorBox)
    {
        AddTreeNode(numberingListWithSeparatorBox, ContentDisplayAction.Select);
        base.VisitNumberingListWithSeparatorBox(numberingListWithSeparatorBox);
    }
    protected override void VisitPageBreakBox(PlainTextBox pageBreakBox)
    {
        AddTreeNode(pageBreakBox, ContentDisplayAction.Select);
        base.VisitPageBreakBox(pageBreakBox);
    }
    protected override void VisitPageNumberBox(PlainTextBox pageNumberBox)
    {
        AddTreeNode(pageNumberBox, ContentDisplayAction.Select);
        base.VisitPageNumberBox(pageNumberBox);
    }
    protected override void VisitParagraphMarkBox(PlainTextBox paragraphMarkBox)
    {
        AddTreeNode(paragraphMarkBox, ContentDisplayAction.Select);
        base.VisitParagraphMarkBox(paragraphMarkBox);
    }
    protected override void VisitPlainTextBox(PlainTextBox plainTextBox)
    {
        AddTreeNode(plainTextBox, ContentDisplayAction.Select);
        base.VisitPlainTextBox(plainTextBox);
    }
    protected override void VisitRangePermissionEndBox(RangePermissionBox rangePermissionEndBox)
    {
        AddTreeNode(rangePermissionEndBox, ContentDisplayAction.Select);
        base.VisitRangePermissionEndBox(rangePermissionEndBox);
    }
    protected override void VisitRangePermissionHighlightAreaBox(RangePermissionHighlightAreaBox rangePermissionHighlightAreaBox)
    {
        AddTreeNode(rangePermissionHighlightAreaBox, ContentDisplayAction.Select);
        base.VisitRangePermissionHighlightAreaBox(rangePermissionHighlightAreaBox);
    }
    protected override void VisitRangePermissionStartBox(RangePermissionBox rangePermissionStartBox)
    {
        AddTreeNode(rangePermissionStartBox, ContentDisplayAction.Select);
        base.VisitRangePermissionStartBox(rangePermissionStartBox);
    }
    protected override void VisitRow(LayoutRow row)
    {
        AddTreeNode(row, ContentDisplayAction.Select);
        base.VisitRow(row);
    }
    protected override void VisitSectionBreakBox(PlainTextBox sectionBreakBox)
    {
        AddTreeNode(sectionBreakBox, ContentDisplayAction.Select);
        base.VisitSectionBreakBox(sectionBreakBox);
    }
    protected override void VisitSpaceBox(PlainTextBox spaceBox)
    {
        AddTreeNode(spaceBox, ContentDisplayAction.Select);
        base.VisitSpaceBox(spaceBox);
    }
    protected override void VisitSpecialTextBox(PlainTextBox specialTextBox)
    {
        AddTreeNode(specialTextBox, ContentDisplayAction.Select);
        base.VisitSpecialTextBox(specialTextBox);
    }
    protected override void VisitStrikeoutBox(StrikeoutBox strikeoutBox)
    {
        AddTreeNode(strikeoutBox, ContentDisplayAction.Select);
        base.VisitStrikeoutBox(strikeoutBox);
    }
    protected override void VisitTable(LayoutTable table)
    {
        AddTreeNode(table, ContentDisplayAction.Select);
        base.VisitTable(table);
    }
    protected override void VisitTableCell(LayoutTableCell tableCell)
    {
        AddTreeNode(tableCell, ContentDisplayAction.Select);
        base.VisitTableCell(tableCell);
    }
    protected override void VisitTableRow(LayoutTableRow tableRow)
    {
        AddTreeNode(tableRow, ContentDisplayAction.Select);
        base.VisitTableRow(tableRow);
    }
    protected override void VisitTabSpaceBox(PlainTextBox tabSpaceBox)
    {
        AddTreeNode(tabSpaceBox, ContentDisplayAction.Select);
        base.VisitTabSpaceBox(tabSpaceBox);
    }
    protected override void VisitTextBox(LayoutTextBox textBox)
    {
        AddTreeNode(textBox, ContentDisplayAction.ScrollTo);
        base.VisitTextBox(textBox);
    }
    protected override void VisitUnderlineBox(UnderlineBox underlineBox)
    {
        AddTreeNode(underlineBox, ContentDisplayAction.Select);
        base.VisitUnderlineBox(underlineBox);
    }

    void AddTreeNode(LayoutElement element, ContentDisplayAction displayActionType)
    {
        TreeNode item = new TreeNode();
        // Store the attribute that determines whether document range selection is allowed for this node.
        item.Tag = displayActionType;
        Rectangle bounds = element.Bounds;
        item.ToolTipText = String.Format("X = {0}\nY = {1}\nWidth = {2}\nHeight = {3}", bounds.X, bounds.Y, bounds.Width, bounds.Height);
        // Update the layout element / tree node dictionary.
        Dictionary.Add(element, item);

        TreeNode parentItem = Dictionary[element.Parent];
        if (parentItem != null) 
        {
            // Add a new node to the tree.
            int index = parentItem.Nodes.Add(item);
            // Specify the node caption.
            string typeName = element.Type.ToString();
            switch (element.Type)
            {
                case LayoutType.Column:
                    item.Text = String.Format("{0} #{1}", typeName, index);
                    break;
                case LayoutType.Row:
                    item.Text = String.Format("{0} #{1}", typeName, index + 1);
                    break;
                case LayoutType.TableRow:
                    item.Text = String.Format("{0} #{1}", typeName, index);
                    break;
                default:
                    item.Text = typeName;
                    break;
            }

            if (parentItem.Tag != null)
            {
                // As for the node that does not allow range selection in the document, all its child nodes should have the same attribute.
                ContentDisplayAction parentDisplayActionType = (ContentDisplayAction)parentItem.Tag;
                ContentDisplayAction actionType = parentDisplayActionType == ContentDisplayAction.ScrollTo ? parentDisplayActionType : displayActionType;
                item.Tag = actionType;
            }
        }
    }
}

public enum ContentDisplayAction { Select, ScrollTo }

Form1.vb

Friend Class TreeViewCollector
    Inherits LayoutVisitor


    Private ReadOnly view_Renamed As TreeView

    Private dictionary_Renamed As Dictionary(Of LayoutElement, TreeNode)

    Private richEdit_Renamed As RichEditControl

    Public Sub New(ByVal view As TreeView, ByVal richEdit As RichEditControl)
        Me.view_Renamed = view
        Me.dictionary_Renamed = New Dictionary(Of LayoutElement, TreeNode)()
        Me.richEdit_Renamed = richEdit
    End Sub

    Public ReadOnly Property View() As TreeView
        Get
            Return view_Renamed
        End Get
    End Property
    Public ReadOnly Property Dictionary() As Dictionary(Of LayoutElement, TreeNode)
        Get
            Return dictionary_Renamed
        End Get
    End Property
    Public ReadOnly Property RichEdit() As RichEditControl
        Get
            Return richEdit_Renamed
        End Get
    End Property

    Protected Overrides Sub VisitPage(ByVal page As LayoutPage)
        Dim item As New TreeNode()
        item.Text = String.Format("{0} #{1}", "Page", page.Index + 1)

        Dictionary.Add(page, item)
        MyBase.VisitPage(page)
        View.Nodes.Add(item)
    End Sub
    Protected Overrides Sub VisitHeader(ByVal header As LayoutHeader)
        AddTreeNode(header, ContentDisplayAction.ScrollTo)
        MyBase.VisitHeader(header)
    End Sub
    Protected Overrides Sub VisitFooter(ByVal footer As LayoutFooter)
        AddTreeNode(footer, ContentDisplayAction.ScrollTo)
        MyBase.VisitFooter(footer)
    End Sub
    Protected Overrides Sub VisitPageArea(ByVal pageArea As LayoutPageArea)
        AddTreeNode(pageArea, ContentDisplayAction.Select)
        MyBase.VisitPageArea(pageArea)
    End Sub
    Protected Overrides Sub VisitBookmarkEndBox(ByVal bookmarkEndBox As BookmarkBox)
        AddTreeNode(bookmarkEndBox, ContentDisplayAction.Select)
        MyBase.VisitBookmarkEndBox(bookmarkEndBox)
    End Sub
    Protected Overrides Sub VisitBookmarkStartBox(ByVal bookmarkStartBox As BookmarkBox)
        AddTreeNode(bookmarkStartBox, ContentDisplayAction.Select)
        MyBase.VisitBookmarkStartBox(bookmarkStartBox)
    End Sub
    Protected Overrides Sub VisitColumn(ByVal column As LayoutColumn)
        AddTreeNode(column, ContentDisplayAction.Select)
        MyBase.VisitColumn(column)
    End Sub
    Protected Overrides Sub VisitColumnBreakBox(ByVal columnBreakBox As PlainTextBox)
        AddTreeNode(columnBreakBox, ContentDisplayAction.Select)
        MyBase.VisitColumnBreakBox(columnBreakBox)
    End Sub
    Protected Overrides Sub VisitComment(ByVal comment As LayoutComment)
        AddTreeNode(comment, ContentDisplayAction.ScrollTo)
        MyBase.VisitComment(comment)
    End Sub
    Protected Overrides Sub VisitCommentEndBox(ByVal commentEndBox As CommentBox)
        AddTreeNode(commentEndBox, ContentDisplayAction.Select)
        MyBase.VisitCommentEndBox(commentEndBox)
    End Sub
    Protected Overrides Sub VisitCommentHighlightAreaBox(ByVal commentHighlightAreaBox As CommentHighlightAreaBox)
        AddTreeNode(commentHighlightAreaBox, ContentDisplayAction.Select)
        MyBase.VisitCommentHighlightAreaBox(commentHighlightAreaBox)
    End Sub
    Protected Overrides Sub VisitCommentStartBox(ByVal commentStartBox As CommentBox)
        AddTreeNode(commentStartBox, ContentDisplayAction.Select)
        MyBase.VisitCommentStartBox(commentStartBox)
    End Sub
    Protected Overrides Sub VisitFieldHighlightAreaBox(ByVal fieldHighlightAreaBox As FieldHighlightAreaBox)
        AddTreeNode(fieldHighlightAreaBox, ContentDisplayAction.Select)
        MyBase.VisitFieldHighlightAreaBox(fieldHighlightAreaBox)
    End Sub
    Protected Overrides Sub VisitFloatingObjectAnchorBox(ByVal floatingObjectAnchorBox As FloatingObjectAnchorBox)
        AddTreeNode(floatingObjectAnchorBox, ContentDisplayAction.Select)
        MyBase.VisitFloatingObjectAnchorBox(floatingObjectAnchorBox)
    End Sub
    Protected Overrides Sub VisitFloatingPicture(ByVal floatingPicture As LayoutFloatingPicture)
        AddTreeNode(floatingPicture, ContentDisplayAction.ScrollTo)
        MyBase.VisitFloatingPicture(floatingPicture)
    End Sub
    Protected Overrides Sub VisitHiddenTextUnderlineBox(ByVal hiddenTextUnderlineBox As HiddenTextUnderlineBox)
        AddTreeNode(hiddenTextUnderlineBox, ContentDisplayAction.Select)
        MyBase.VisitHiddenTextUnderlineBox(hiddenTextUnderlineBox)
    End Sub
    Protected Overrides Sub VisitHighlightAreaBox(ByVal highlightAreaBox As HighlightAreaBox)
        AddTreeNode(highlightAreaBox, ContentDisplayAction.Select)
        MyBase.VisitHighlightAreaBox(highlightAreaBox)
    End Sub
    Protected Overrides Sub VisitHyphenBox(ByVal hyphen As PlainTextBox)
        AddTreeNode(hyphen, ContentDisplayAction.Select)
        MyBase.VisitHyphenBox(hyphen)
    End Sub
    Protected Overrides Sub VisitInlinePictureBox(ByVal inlinePictureBox As InlinePictureBox)
        AddTreeNode(inlinePictureBox, ContentDisplayAction.Select)
        MyBase.VisitInlinePictureBox(inlinePictureBox)
    End Sub
    Protected Overrides Sub VisitLineBreakBox(ByVal lineBreakBox As PlainTextBox)
        AddTreeNode(lineBreakBox, ContentDisplayAction.Select)
        MyBase.VisitLineBreakBox(lineBreakBox)
    End Sub
    Protected Overrides Sub VisitLineNumberBox(ByVal lineNumberBox As LineNumberBox)
        AddTreeNode(lineNumberBox, ContentDisplayAction.Select)
        MyBase.VisitLineNumberBox(lineNumberBox)
    End Sub
    Protected Overrides Sub VisitNumberingListMarkBox(ByVal numberingListMarkBox As NumberingListMarkBox)
        AddTreeNode(numberingListMarkBox, ContentDisplayAction.Select)
        MyBase.VisitNumberingListMarkBox(numberingListMarkBox)
    End Sub
    Protected Overrides Sub VisitNumberingListWithSeparatorBox(ByVal numberingListWithSeparatorBox As NumberingListWithSeparatorBox)
        AddTreeNode(numberingListWithSeparatorBox, ContentDisplayAction.Select)
        MyBase.VisitNumberingListWithSeparatorBox(numberingListWithSeparatorBox)
    End Sub
    Protected Overrides Sub VisitPageBreakBox(ByVal pageBreakBox As PlainTextBox)
        AddTreeNode(pageBreakBox, ContentDisplayAction.Select)
        MyBase.VisitPageBreakBox(pageBreakBox)
    End Sub
    Protected Overrides Sub VisitPageNumberBox(ByVal pageNumberBox As PlainTextBox)
        AddTreeNode(pageNumberBox, ContentDisplayAction.Select)
        MyBase.VisitPageNumberBox(pageNumberBox)
    End Sub
    Protected Overrides Sub VisitParagraphMarkBox(ByVal paragraphMarkBox As PlainTextBox)
        AddTreeNode(paragraphMarkBox, ContentDisplayAction.Select)
        MyBase.VisitParagraphMarkBox(paragraphMarkBox)
    End Sub
    Protected Overrides Sub VisitPlainTextBox(ByVal plainTextBox As PlainTextBox)
        AddTreeNode(plainTextBox, ContentDisplayAction.Select)
        MyBase.VisitPlainTextBox(plainTextBox)
    End Sub
    Protected Overrides Sub VisitRangePermissionEndBox(ByVal rangePermissionEndBox As RangePermissionBox)
        AddTreeNode(rangePermissionEndBox, ContentDisplayAction.Select)
        MyBase.VisitRangePermissionEndBox(rangePermissionEndBox)
    End Sub
    Protected Overrides Sub VisitRangePermissionHighlightAreaBox(ByVal rangePermissionHighlightAreaBox As RangePermissionHighlightAreaBox)
        AddTreeNode(rangePermissionHighlightAreaBox, ContentDisplayAction.Select)
        MyBase.VisitRangePermissionHighlightAreaBox(rangePermissionHighlightAreaBox)
    End Sub
    Protected Overrides Sub VisitRangePermissionStartBox(ByVal rangePermissionStartBox As RangePermissionBox)
        AddTreeNode(rangePermissionStartBox, ContentDisplayAction.Select)
        MyBase.VisitRangePermissionStartBox(rangePermissionStartBox)
    End Sub
    Protected Overrides Sub VisitRow(ByVal row As LayoutRow)
        AddTreeNode(row, ContentDisplayAction.Select)
        MyBase.VisitRow(row)
    End Sub
    Protected Overrides Sub VisitSectionBreakBox(ByVal sectionBreakBox As PlainTextBox)
        AddTreeNode(sectionBreakBox, ContentDisplayAction.Select)
        MyBase.VisitSectionBreakBox(sectionBreakBox)
    End Sub
    Protected Overrides Sub VisitSpaceBox(ByVal spaceBox As PlainTextBox)
        AddTreeNode(spaceBox, ContentDisplayAction.Select)
        MyBase.VisitSpaceBox(spaceBox)
    End Sub
    Protected Overrides Sub VisitSpecialTextBox(ByVal specialTextBox As PlainTextBox)
        AddTreeNode(specialTextBox, ContentDisplayAction.Select)
        MyBase.VisitSpecialTextBox(specialTextBox)
    End Sub
    Protected Overrides Sub VisitStrikeoutBox(ByVal strikeoutBox As StrikeoutBox)
        AddTreeNode(strikeoutBox, ContentDisplayAction.Select)
        MyBase.VisitStrikeoutBox(strikeoutBox)
    End Sub
    Protected Overrides Sub VisitTable(ByVal table As LayoutTable)
        AddTreeNode(table, ContentDisplayAction.Select)
        MyBase.VisitTable(table)
    End Sub
    Protected Overrides Sub VisitTableCell(ByVal tableCell As LayoutTableCell)
        AddTreeNode(tableCell, ContentDisplayAction.Select)
        MyBase.VisitTableCell(tableCell)
    End Sub
    Protected Overrides Sub VisitTableRow(ByVal tableRow As LayoutTableRow)
        AddTreeNode(tableRow, ContentDisplayAction.Select)
        MyBase.VisitTableRow(tableRow)
    End Sub
    Protected Overrides Sub VisitTabSpaceBox(ByVal tabSpaceBox As PlainTextBox)
        AddTreeNode(tabSpaceBox, ContentDisplayAction.Select)
        MyBase.VisitTabSpaceBox(tabSpaceBox)
    End Sub
    Protected Overrides Sub VisitTextBox(ByVal textBox As LayoutTextBox)
        AddTreeNode(textBox, ContentDisplayAction.ScrollTo)
        MyBase.VisitTextBox(textBox)
    End Sub
    Protected Overrides Sub VisitUnderlineBox(ByVal underlineBox As UnderlineBox)
        AddTreeNode(underlineBox, ContentDisplayAction.Select)
        MyBase.VisitUnderlineBox(underlineBox)
    End Sub

    Private Sub AddTreeNode(ByVal element As LayoutElement, ByVal displayActionType As ContentDisplayAction)
        Dim item As New TreeNode()
        ' Store the attribute that determines whether document range selection is allowed for this node.
        item.Tag = displayActionType
        Dim bounds As Rectangle = element.Bounds
        item.ToolTipText = String.Format("X = {0}" & ControlChars.Lf & "Y = {1}" & ControlChars.Lf & "Width = {2}" & ControlChars.Lf & "Height = {3}", bounds.X, bounds.Y, bounds.Width, bounds.Height)
        ' Update the layout element / tree node dictionary.
        Dictionary.Add(element, item)

        Dim parentItem As TreeNode = Dictionary(element.Parent)
        If parentItem IsNot Nothing Then
            ' Add a new node to the tree.
            Dim index As Integer = parentItem.Nodes.Add(item)
            ' Specify the node caption.
            Dim typeName As String = element.Type.ToString()
            Select Case element.Type
                Case LayoutType.Column
                    item.Text = String.Format("{0} #{1}", typeName, index)
                Case LayoutType.Row
                    item.Text = String.Format("{0} #{1}", typeName, index + 1)
                Case LayoutType.TableRow
                    item.Text = String.Format("{0} #{1}", typeName, index)
                Case Else
                    item.Text = typeName
            End Select

            If parentItem.Tag IsNot Nothing Then
                ' As for the node that does not allow range selection in the document, all its child nodes should have the same attribute.
                Dim parentDisplayActionType As ContentDisplayAction = DirectCast(parentItem.Tag, ContentDisplayAction)
                Dim actionType As ContentDisplayAction = If(parentDisplayActionType = ContentDisplayAction.ScrollTo, parentDisplayActionType, displayActionType)
                item.Tag = actionType
            End If
        End If
    End Sub
End Class

Public Enum ContentDisplayAction
    [Select]
    ScrollTo
End Enum

Inheritance

Object

LayoutVisitor