AcceptStart

HeaderFooter.AcceptStart method

Accepts a visitor for visiting the start of the header.

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

Return Value

The action to be taken by the visitor.

Examples

Shows how to print the node structure of every header and footer in a document.

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

    // 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());

    // An alternative way of accessing a document's header/footers section-by-section is by accessing the collection.
    HeaderFooter[] headerFooters = doc.FirstSection.HeadersFooters.ToArray();
    Assert.AreEqual(3, headerFooters.Length);
}

/// <summary>
/// Traverses a node's non-binary tree of child nodes.
/// Creates a map in the form of a string of all encountered HeaderFooter nodes and their children.
/// </summary>
public class HeaderFooterStructurePrinter : DocumentVisitor
{
    public HeaderFooterStructurePrinter()
    {
        mBuilder = new StringBuilder();
        mVisitorIsInsideHeaderFooter = false;
    }

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

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

        return VisitorAction.Continue;
    }

    /// <summary>
    /// Called when a HeaderFooter node is encountered in the document.
    /// </summary>
    public override VisitorAction VisitHeaderFooterStart(HeaderFooter headerFooter)
    {
        IndentAndAppendLine("[HeaderFooter start] HeaderFooterType: " + headerFooter.HeaderFooterType);
        mDocTraversalDepth++;
        mVisitorIsInsideHeaderFooter = true;

        return VisitorAction.Continue;
    }

    /// <summary>
    /// Called after all the child nodes of a HeaderFooter node have been visited.
    /// </summary>
    public override VisitorAction VisitHeaderFooterEnd(HeaderFooter headerFooter)
    {
        mDocTraversalDepth--;
        IndentAndAppendLine("[HeaderFooter end]");
        mVisitorIsInsideHeaderFooter = false;

        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 bool mVisitorIsInsideHeaderFooter;
    private int mDocTraversalDepth;
    private readonly StringBuilder mBuilder;
}

See Also

HeaderFooter.AcceptEnd