AcceptStart

Document.AcceptStart method

Accepts a visitor for visiting the start of the document.

public override VisitorAction AcceptStart(DocumentVisitor visitor)
ParameterTypeDescription
visitorDocumentVisitorThe document visitor.

Return Value

The action to be taken by the visitor.

Examples

Shows how to use a document visitor to print a document’s node structure.

public void DocStructureToText()
{
    Document doc = new Document(MyDir + "DocumentVisitor-compatible features.docx");
    DocStructurePrinter visitor = new DocStructurePrinter();

    // When we get a composite node to accept a document visitor, the visitor visits the accepting node,
    // and then traverses all the node's children in a depth-first manner.
    // The visitor can read and modify each visited node.
    doc.Accept(visitor);

    Console.WriteLine(visitor.GetText());
}

/// <summary>
/// Traverses a node's tree of child nodes.
/// Creates a map of this tree in the form of a string.
/// </summary>
public class DocStructurePrinter : DocumentVisitor
{
    public DocStructurePrinter()
    {
        mAcceptingNodeChildTree = new StringBuilder();
    }

    public string GetText()
    {
        return mAcceptingNodeChildTree.ToString();
    }

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

        IndentAndAppendLine("[Document start] Child nodes: " + childNodeCount);
        mDocTraversalDepth++;

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

    /// <summary>
    /// Called after all the child nodes of a Document node have been visited.
    /// </summary>
    public override VisitorAction VisitDocumentEnd(Document doc)
    {
        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 after all the child nodes of a Section node have been visited.
    /// </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 after all the child nodes of a Body node have been visited.
    /// </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 after all the child nodes of a Paragraph node have been visited.
    /// </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>
    /// Called when a SubDocument node is encountered in the document.
    /// </summary>
    public override VisitorAction VisitStructuredDocumentTagRangeStart(StructuredDocumentTagRangeStart sdtRangeStart)
    {
        IndentAndAppendLine("[SdtRangeStart]");

        return VisitorAction.Continue;
    }

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

        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++) mAcceptingNodeChildTree.Append("|  ");

        mAcceptingNodeChildTree.AppendLine(text);
    }

    private int mDocTraversalDepth;
    private readonly StringBuilder mAcceptingNodeChildTree;
}

See Also

Document.AcceptEnd Document.AppendDocument