Aspose.Words for .NET. Change or replace header and footer using C#.

create-header-footer-aspose-words.cs

// For complete examples and data files, please go to https://github.com/aspose-words/Aspose.Words-for-.NET.git.
Document doc = new Document();
DocumentBuilder builder = new DocumentBuilder(doc);

builder.MoveToHeaderFooter(HeaderFooterType.HeaderPrimary);
builder.Write("Aspose.Words Header");
builder.MoveToHeaderFooter(HeaderFooterType.FooterPrimary);
builder.Write("Aspose.Words Footer");

doc.Save(ArtifactsDir + "Create header footer - Aspose.Words.docx");

create-header-footer-open-xml.cs

// For complete examples and data files, please go to https://github.com/aspose-words/Aspose.Words-for-.NET.git.
public void CreateHeaderFooterOpenXml()
{
    // Create a new Word document.
    using WordprocessingDocument document = WordprocessingDocument.Create(ArtifactsDir + "Create header footer - OpenXML.docx",
        WordprocessingDocumentType.Document);

    // Add a main document part.
    MainDocumentPart mainDocumentPart = document.AddMainDocumentPart();
    mainDocumentPart.Document = new Document(new Body());

    // Delete existing header and footer parts (if any).
    mainDocumentPart.DeleteParts(mainDocumentPart.HeaderParts);
    mainDocumentPart.DeleteParts(mainDocumentPart.FooterParts);

    // Add new header and footer parts.
    HeaderPart headerPart = mainDocumentPart.AddNewPart<HeaderPart>();
    FooterPart footerPart = mainDocumentPart.AddNewPart<FooterPart>();

    string headerPartId = mainDocumentPart.GetIdOfPart(headerPart);
    string footerPartId = mainDocumentPart.GetIdOfPart(footerPart);

    // Generate content for the header and footer.
    GenerateHeaderPartContent(headerPart);
    GenerateFooterPartContent(footerPart);

    // Ensure the document has at least one section.
    if (mainDocumentPart.Document.Body.Elements<SectionProperties>().Count() == 0)
        mainDocumentPart.Document.Body.AppendChild(new SectionProperties());

    // Assign the header and footer to all sections.
    IEnumerable<SectionProperties> sections = mainDocumentPart.Document.Body.Elements<SectionProperties>();
    foreach (var section in sections)
    {
        section.RemoveAllChildren<HeaderReference>();
        section.RemoveAllChildren<FooterReference>();

        section.PrependChild(new HeaderReference { Id = headerPartId });
        section.PrependChild(new FooterReference { Id = footerPartId });
    }

    mainDocumentPart.Document.Save();
}

private void GenerateHeaderPartContent(HeaderPart part)
{
    Header header = new Header();

    Paragraph paragraph = new Paragraph { RsidParagraphAddition = "00164C17", RsidRunAdditionDefault = "00164C17" };

    ParagraphProperties paragraphProperties = new ParagraphProperties();
    ParagraphStyleId paragraphStyleId = new ParagraphStyleId { Val = "Header" };

    paragraphProperties.Append(paragraphStyleId);

    Run run = new Run();
    Text text = new Text { Text = "Header" };

    run.Append(text);
    paragraph.Append(paragraphProperties);
    paragraph.Append(run);

    header.Append(paragraph);

    part.Header = header;
}

private void GenerateFooterPartContent(FooterPart part)
{
    Footer footer = new Footer();

    Paragraph paragraph = new Paragraph { RsidParagraphAddition = "00164C17", RsidRunAdditionDefault = "00164C17" };

    ParagraphProperties paragraphProperties = new ParagraphProperties();
    ParagraphStyleId paragraphStyleId = new ParagraphStyleId { Val = "Footer" };

    paragraphProperties.Append(paragraphStyleId);

    Run run = new Run();
    Text text = new Text { Text = "Footer" };

    run.Append(text);
    paragraph.Append(paragraphProperties);
    paragraph.Append(run);

    footer.Append(paragraph);

    part.Footer = footer;
}