DocumentVisitor Class
Base class for custom document visitors.
Inheritance Hierarchy
SystemObject
  Aspose.WordsDocumentVisitor

Namespace: Aspose.Words
Assembly: Aspose.Words (in Aspose.Words.dll) Version: 19.11
Syntax
public abstract class DocumentVisitor

The DocumentVisitor type exposes the following members.

Constructors
  NameDescription
Protected methodDocumentVisitor
Initializes a new instance of the DocumentVisitor class
Methods
  NameDescription
Public methodEquals (Inherited from Object.)
Protected methodFinalize (Inherited from Object.)
Public methodGetHashCode (Inherited from Object.)
Public methodGetType (Inherited from Object.)
Protected methodMemberwiseClone (Inherited from Object.)
Public methodToString (Inherited from Object.)
Public methodCode exampleVisitAbsolutePositionTab
Called when a AbsolutePositionTab node is encountered in the document.
Public methodCode exampleVisitBodyEnd
Called when enumeration of the main text story in a section has ended.
Public methodCode exampleVisitBodyStart
Called when enumeration of the main text story in a section has started.
Public methodCode exampleVisitBookmarkEnd
Called when an end of a bookmark is encountered in the document.
Public methodCode exampleVisitBookmarkStart
Called when a start of a bookmark is encountered in the document.
Public methodCode exampleVisitBuildingBlockEnd
Called when enumeration of a building block has ended.
Public methodCode exampleVisitBuildingBlockStart
Called when enumeration of a building block has started.
Public methodCode exampleVisitCellEnd
Called when enumeration of a table cell has ended.
Public methodCode exampleVisitCellStart
Called when enumeration of a table cell has started.
Public methodCode exampleVisitCommentEnd
Called when enumeration of a comment text has ended.
Public methodCode exampleVisitCommentRangeEnd
Called when the end of a commented range of text is encountered.
Public methodCode exampleVisitCommentRangeStart
Called when the start of a commented range of text is encountered.
Public methodCode exampleVisitCommentStart
Called when enumeration of a comment text has started.
Public methodCode exampleVisitDocumentEnd
Called when enumeration of the document has finished.
Public methodCode exampleVisitDocumentStart
Called when enumeration of the document has started.
Public methodCode exampleVisitEditableRangeEnd
Called when an end of an editable range is encountered in the document.
Public methodCode exampleVisitEditableRangeStart
Called when a start of an editable range is encountered in the document.
Public methodCode exampleVisitFieldEnd
Called when a field ends in the document.
Public methodCode exampleVisitFieldSeparator
Called when a field separator is encountered in the document.
Public methodCode exampleVisitFieldStart
Called when a field starts in the document.
Public methodCode exampleVisitFootnoteEnd
Called when enumeration of a footnote or endnote text has ended.
Public methodCode exampleVisitFootnoteStart
Called when enumeration of a footnote or endnote text has started.
Public methodCode exampleVisitFormField
Called when a form field is encountered in the document.
Public methodCode exampleVisitGlossaryDocumentEnd
Called when enumeration of a glossary document has ended.
Public methodCode exampleVisitGlossaryDocumentStart
Called when enumeration of a glossary document has started.
Public methodCode exampleVisitGroupShapeEnd
Called when enumeration of a group shape has ended.
Public methodCode exampleVisitGroupShapeStart
Called when enumeration of a group shape has started.
Public methodCode exampleVisitHeaderFooterEnd
Called when enumeration of a header or footer in a section has ended.
Public methodCode exampleVisitHeaderFooterStart
Called when enumeration of a header or footer in a section has started.
Public methodCode exampleVisitOfficeMathEnd
Called when enumeration of a Office Math object has ended.
Public methodCode exampleVisitOfficeMathStart
Called when enumeration of a Office Math object has started.
Public methodCode exampleVisitParagraphEnd
Called when enumeration of a paragraph has ended.
Public methodCode exampleVisitParagraphStart
Called when enumeration of a paragraph has started.
Public methodCode exampleVisitRowEnd
Called when enumeration of a table row has ended.
Public methodCode exampleVisitRowStart
Called when enumeration of a table row has started.
Public methodCode exampleVisitRun
Called when a run of text in the is encountered.
Public methodCode exampleVisitSectionEnd
Called when enumeration of a section has ended.
Public methodCode exampleVisitSectionStart
Called when enumeration of a section has started.
Public methodCode exampleVisitShapeEnd
Called when enumeration of a shape has ended.
Public methodCode exampleVisitShapeStart
Called when enumeration of a shape has started.
Public methodCode exampleVisitSmartTagEnd
Called when enumeration of a smart tag has ended.
Public methodCode exampleVisitSmartTagStart
Called when enumeration of a smart tag has started.
Public methodCode exampleVisitSpecialChar
Called when a SpecialChar node is encountered in the document.
Public methodCode exampleVisitStructuredDocumentTagEnd
Called when enumeration of a structured document tag has ended.
Public methodCode exampleVisitStructuredDocumentTagStart
Called when enumeration of a structured document tag has started.
Public methodCode exampleVisitSubDocument
Called when a subDocument is encountered.
Public methodCode exampleVisitTableEnd
Called when enumeration of a table has ended.
Public methodCode exampleVisitTableStart
Called when enumeration of a table has started.
Remarks

With DocumentVisitor you can define and execute custom operations that require enumeration over the document tree.

For example, Aspose.Words uses DocumentVisitor internally for saving Document in various formats and for other operations like finding fields or bookmarks over a fragment of a document.

To use DocumentVisitor:

  1. Create a class derived from DocumentVisitor.
  2. Override and provide implementations for some or all of the VisitXXX methods to perform some custom operations.
  3. Call Node.Accept on the Node that you want to start the enumeration from.

DocumentVisitor provides default implementations for all of the VisitXXX methods to make it easier to create new document visitors as only the methods required for the particular visitor need to be overridden. It is not necessary to override all of the visitor methods.

For more information see the Visitor design pattern.

Examples
Traverse a document with a visitor that prints all structure nodes that it encounters.
public void DocStructureToText()
{
    // Open the document that has nodes we want to print the info of
    Document doc = new Document(MyDir + "DocumentVisitor.Destination.docx");

    // Create an object that inherits from the DocumentVisitor class
    DocStructurePrinter visitor = new DocStructurePrinter();

    // Accepting a visitor lets it start traversing the nodes in the document, 
    // starting with the node that accepted it to then recursively visit every child
    doc.Accept(visitor);

    // Once the visiting is complete, we can retrieve the result of the operation,
    // that in this example, has accumulated in the visitor
    Console.WriteLine(visitor.GetText());
}

/// <summary>
/// This Visitor implementation prints information about sections, bodies, paragraphs and runs encountered in the document.
/// </summary>
public class DocStructurePrinter : DocumentVisitor
{
    public DocStructurePrinter()
    {
        mBuilder = new StringBuilder();
    }

    /// <summary>
    /// Gets the plain text of the document that was accumulated by the visitor.
    /// </summary>
    public string GetText()
    {
        return mBuilder.ToString();
    }

    /// <summary>
    /// Called when a Document node is encountered.
    /// </summary>
    public override VisitorAction VisitDocumentStart(Document doc)
    {
        int childNodeCount = doc.GetChildNodes(NodeType.Any, true).Count;

        // A Document node is at the root of every document, so if we let a document accept a visitor, this will be the first visitor action to be carried out
        IndentAndAppendLine("[Document start] Child nodes: " + childNodeCount);
        mDocTraversalDepth++;

        // Let the visitor continue visiting other nodes
        return VisitorAction.Continue;
    }

    /// <summary>
    /// Called when the visiting of a Document is ended.
    /// </summary>
    public override VisitorAction VisitDocumentEnd(Document doc)
    {
        // If we let a document accept a visitor, this will be the last visitor action to be carried out
        mDocTraversalDepth--;
        IndentAndAppendLine("[Document end]");

        return VisitorAction.Continue;
    }

    /// <summary>
    /// Called when a Section node is encountered in the document.
    /// </summary>
    public override VisitorAction VisitSectionStart(Section section)
    {
        // Get the index of our section within the document
        NodeCollection docSections = section.Document.GetChildNodes(NodeType.Section, false);
        int sectionIndex = docSections.IndexOf(section);

        IndentAndAppendLine("[Section start] Section index: " + sectionIndex);
        mDocTraversalDepth++;

        return VisitorAction.Continue;
    }

    /// <summary>
    /// Called when the visiting of a Section node is ended.
    /// </summary>
    public override VisitorAction VisitSectionEnd(Section section)
    {
        mDocTraversalDepth--;
        IndentAndAppendLine("[Section end]");

        return VisitorAction.Continue;
    }

    /// <summary>
    /// Called when a Body node is encountered in the document.
    /// </summary>
    public override VisitorAction VisitBodyStart(Body body)
    {
        int paragraphCount = body.Paragraphs.Count;
        IndentAndAppendLine("[Body start] Paragraphs: " + paragraphCount);
        mDocTraversalDepth++;

        return VisitorAction.Continue;
    }

    /// <summary>
    /// Called when the visiting of a Body node is ended.
    /// </summary>
    public override VisitorAction VisitBodyEnd(Body body)
    {
        mDocTraversalDepth--;
        IndentAndAppendLine("[Body end]");

        return VisitorAction.Continue;
    }

    /// <summary>
    /// Called when a Paragraph node is encountered in the document.
    /// </summary>
    public override VisitorAction VisitParagraphStart(Paragraph paragraph)
    {
        IndentAndAppendLine("[Paragraph start]");
        mDocTraversalDepth++;

        return VisitorAction.Continue;
    }

    /// <summary>
    /// Called when the visiting of a Paragraph node is ended.
    /// </summary>
    public override VisitorAction VisitParagraphEnd(Paragraph paragraph)
    {
        mDocTraversalDepth--;
        IndentAndAppendLine("[Paragraph end]");

        return VisitorAction.Continue;
    }

    /// <summary>
    /// Called when a Run node is encountered in the document.
    /// </summary>
    public override VisitorAction VisitRun(Run run)
    {
        IndentAndAppendLine("[Run] \"" + run.GetText() + "\"");

        return VisitorAction.Continue;
    }

    /// <summary>
    /// Called when a SubDocument node is encountered in the document.
    /// </summary>
    public override VisitorAction VisitSubDocument(SubDocument subDocument)
    {
        IndentAndAppendLine("[SubDocument]");

        return VisitorAction.Continue;
    }

    /// <summary>
    /// Append a line to the StringBuilder and indent it depending on how deep the visitor is into the document tree.
    /// </summary>
    /// <param name="text"></param>
    private void IndentAndAppendLine(String text)
    {
        for (int i = 0; i < mDocTraversalDepth; i++)
        {
            mBuilder.Append("|  ");
        }

        mBuilder.AppendLine(text);
    }

    private int mDocTraversalDepth;
    private readonly StringBuilder mBuilder;
}
See Also