How to merge word documents with different headers using openxml? - ms-word

Question

I am trying to merge multiple documents into a single one by following examples as posted in this other post.
I am using AltChunk altChunk = new AltChunk(). When documents are merged, it does not seem to retain seperate hearders of each document. The merged document will contain the headers of the first document during the merging. If the first document being merged contains no hearders, then all the rest of the newly merged document will contain no headers, and vise versa.
My question is, how can I preserve different headers of the documents being merged?
Merge multiple word documents into one Open Xml
using System;
using System.IO;
using System.Linq;
using DocumentFormat.OpenXml.Packaging;
using DocumentFormat.OpenXml.Wordprocessing;
namespace WordMergeProject
{
public class Program
{
private static void Main(string[] args)
{
byte[] word1 = File.ReadAllBytes(#"..\..\word1.docx");
byte[] word2 = File.ReadAllBytes(#"..\..\word2.docx");
byte[] result = Merge(word1, word2);
File.WriteAllBytes(#"..\..\word3.docx", result);
}
private static byte[] Merge(byte[] dest, byte[] src)
{
string altChunkId = "AltChunkId" + DateTime.Now.Ticks.ToString();
var memoryStreamDest = new MemoryStream();
memoryStreamDest.Write(dest, 0, dest.Length);
memoryStreamDest.Seek(0, SeekOrigin.Begin);
var memoryStreamSrc = new MemoryStream(src);
using (WordprocessingDocument doc = WordprocessingDocument.Open(memoryStreamDest, true))
{
MainDocumentPart mainPart = doc.MainDocumentPart;
AlternativeFormatImportPart altPart =
mainPart.AddAlternativeFormatImportPart(AlternativeFormatImportPartType.WordprocessingML, altChunkId);
altPart.FeedData(memoryStreamSrc);
var altChunk = new AltChunk();
altChunk.Id = altChunkId;
OpenXmlElement lastElem = mainPart.Document.Body.Elements<AltChunk>().LastOrDefault();
if(lastElem == null)
{
lastElem = mainPart.Document.Body.Elements<Paragraph>().Last();
}
//Page Brake einfügen
Paragraph pageBreakP = new Paragraph();
Run pageBreakR = new Run();
Break pageBreakBr = new Break() { Type = BreakValues.Page };
pageBreakP.Append(pageBreakR);
pageBreakR.Append(pageBreakBr);
return memoryStreamDest.ToArray();
}
}
}

Answer 1

I encountered this question a few years ago and spent quite some time on it; I eventually wrote a blog article that links to a sample file. Achieving integrating files with headers and footers using Alt-Chunk is not straight-forward. I'll try to cover the essentials, here. Depending on what kinds of content the headers and footers contain (and assuming Microsoft has not addressed any of the problems I originally ran into) it may not be possible to rely soley on AltChunk.
(Note also that there may be Tools/APIs that can handle this - I don't know and asking that on this site would be off-topic.)
Background
Before attacking the problem, it helps to understand how Word handles different headers and footers. To get a feel for it, start Word...
Section Breaks / Unlinking headers/footers
Type some text on the page and insert a header
Move the focus to the end of the page and go to the Page Layout tab in the Ribbon
Page Setup/Breaks/Next Page section break
Go into the Header area for this page and note the information in the blue "tags": you'll see a section identifier on the left and "Same as previous" on the right. "Same as Previous" is the default, to create a different Header click the "Link to Previous" button in the Header
So, the rule is:
a section break is required, with unlinked headers (and/or footers),
in order to have different header/footer content within a document.
Master/Sub-documents
Word has an (in)famous functionality called "Master Document" that enables linking outside ("sub") documents into a "master" document. Doing so automatically adds the necessary section breaks and unlinks the headers/footers so that the originals are retained.
Go to Word's Outline view
Click "Show Document"
Use "Insert" to insert other files
Notice that two section breaks are inserted, one of the type "Next page" and the other "Continuous". The first is inserted in the file coming in; the second in the "master" file.
Two section breaks are necessary when inserting a file because the last paragraph mark (which contains the section break for the end of the document) is not carried over to the target document. The section break in the target document carries the information to unlink the in-coming header from those already in the target document.
When the master is saved, closed and re-opened the sub documents are in a "collapsed" state (file names as hyperlinks instead of the content). They can be expanded by going back to the Outline view and clicking the "Expand" button. To fully incorporate a sub-document into the document click on the icon at the top left next to a sub-document then clicking "Unlink".
Merging Word Open XML files
This, then, is the type of environment the Open XML SDK needs to create when merging files whose headers and footers need to be retained. Theoretically, either approach should work. Practically, I had problems with using only section breaks; I've never tested using the Master Document feature in Word Open XML.
Inserting section breaks
Here's the basic code for inserting a section break and unlinking headers before bringing in a file using AltChunk. Looking at my old posts and articles, as long as there's no complex page numbering involved, it works:
private void btnMergeWordDocs_Click(object sender, EventArgs e)
{
string sourceFolder = #"C:\Test\MergeDocs\";
string targetFolder = #"C:\Test\";
string altChunkIdBase = "acID";
int altChunkCounter = 1;
string altChunkId = altChunkIdBase + altChunkCounter.ToString();
MainDocumentPart wdDocTargetMainPart = null;
Document docTarget = null;
AlternativeFormatImportPartType afType;
AlternativeFormatImportPart chunk = null;
AltChunk ac = null;
using (WordprocessingDocument wdPkgTarget = WordprocessingDocument.Create(targetFolder + "mergedDoc.docx", DocumentFormat.OpenXml.WordprocessingDocumentType.Document, true))
{
//Will create document in 2007 Compatibility Mode.
//In order to make it 2010 a Settings part must be created and a CompatMode element for the Office version set.
wdDocTargetMainPart = wdPkgTarget.MainDocumentPart;
if (wdDocTargetMainPart == null)
{
wdDocTargetMainPart = wdPkgTarget.AddMainDocumentPart();
Document wdDoc = new Document(
new Body(
new Paragraph(
new Run(new Text() { Text = "First Para" })),
new Paragraph(new Run(new Text() { Text = "Second para" })),
new SectionProperties(
new SectionType() { Val = SectionMarkValues.NextPage },
new PageSize() { Code = 9 },
new PageMargin() { Gutter = 0, Bottom = 1134, Top = 1134, Left = 1318, Right = 1318, Footer = 709, Header = 709 },
new Columns() { Space = "708" },
new TitlePage())));
wdDocTargetMainPart.Document = wdDoc;
}
docTarget = wdDocTargetMainPart.Document;
SectionProperties secPropLast = docTarget.Body.Descendants<SectionProperties>().Last();
SectionProperties secPropNew = (SectionProperties)secPropLast.CloneNode(true);
//A section break must be in a ParagraphProperty
Paragraph lastParaTarget = (Paragraph)docTarget.Body.Descendants<Paragraph>().Last();
ParagraphProperties paraPropTarget = lastParaTarget.ParagraphProperties;
if (paraPropTarget == null)
{
paraPropTarget = new ParagraphProperties();
}
paraPropTarget.Append(secPropNew);
Run paraRun = lastParaTarget.Descendants<Run>().FirstOrDefault();
//lastParaTarget.InsertBefore(paraPropTarget, paraRun);
lastParaTarget.InsertAt(paraPropTarget, 0);
//Process the individual files in the source folder.
//Note that this process will permanently change the files by adding a section break.
System.IO.DirectoryInfo di = new System.IO.DirectoryInfo(sourceFolder);
IEnumerable<System.IO.FileInfo> docFiles = di.EnumerateFiles();
foreach (System.IO.FileInfo fi in docFiles)
{
using (WordprocessingDocument pkgSourceDoc = WordprocessingDocument.Open(fi.FullName, true))
{
IEnumerable<HeaderPart> partsHeader = pkgSourceDoc.MainDocumentPart.GetPartsOfType<HeaderPart>();
IEnumerable<FooterPart> partsFooter = pkgSourceDoc.MainDocumentPart.GetPartsOfType<FooterPart>();
//If the source document has headers or footers we want to retain them.
//This requires inserting a section break at the end of the document.
if (partsHeader.Count() > 0 || partsFooter.Count() > 0)
{
Body sourceBody = pkgSourceDoc.MainDocumentPart.Document.Body;
SectionProperties docSectionBreak = sourceBody.Descendants<SectionProperties>().Last();
//Make a copy of the document section break as this won't be imported into the target document.
//It needs to be appended to the last paragraph of the document
SectionProperties copySectionBreak = (SectionProperties)docSectionBreak.CloneNode(true);
Paragraph lastpara = sourceBody.Descendants<Paragraph>().Last();
ParagraphProperties paraProps = lastpara.ParagraphProperties;
if (paraProps == null)
{
paraProps = new ParagraphProperties();
lastpara.Append(paraProps);
}
paraProps.Append(copySectionBreak);
}
pkgSourceDoc.MainDocumentPart.Document.Save();
}
//Insert the source file into the target file using AltChunk
afType = AlternativeFormatImportPartType.WordprocessingML;
chunk = wdDocTargetMainPart.AddAlternativeFormatImportPart(afType, altChunkId);
System.IO.FileStream fsSourceDocument = new System.IO.FileStream(fi.FullName, System.IO.FileMode.Open);
chunk.FeedData(fsSourceDocument);
//Create the chunk
ac = new AltChunk();
//Link it to the part
ac.Id = altChunkId;
docTarget.Body.InsertAfter(ac, docTarget.Body.Descendants<Paragraph>().Last());
docTarget.Save();
altChunkCounter += 1;
altChunkId = altChunkIdBase + altChunkCounter.ToString();
chunk = null;
ac = null;
}
}
}
If there's complex page numbering (quoted from my blog article):
Unfortunately, there’s a bug in the Word application when integrating
Word document “chunks” into the main document. The process has the
nasty habit of not retaining a number of SectionProperties, among them
the one that sets whether a section has a Different First Page
() and the one to restart Page Numbering () in a section. As long as your documents don’t need to
manage these kinds of headers and footers you can probably use the
“altChunk” approach.
But if you do need to handle complex headers and footers the only
method currently available to you is to copy in the each document in
its entirety, part-by-part. This is a non-trivial undertaking, as
there are numerous possible types of Parts that can be associated not
only with the main document body, but also with each header and footer
part.
...or try the Master/Sub Document approach.
Master/Sub Document
This approach will certainly maintain all information, it will open as a Master document, however, and the Word API (either the user or automation code) is required to "unlink" the sub-documents to turn it into a single, integrated document.
Opening a Master Document file in the Open XML SDK Productivity Tool shows that inserting sub documents into the master document is a fairly straight-forward procedure:
The underlying Word Open XML for the document with one sub-document:
<w:body xmlns:w="http://schemas.openxmlformats.org/wordprocessingml/2006/main">
<w:p>
<w:pPr>
<w:pStyle w:val="Heading1" />
</w:pPr>
<w:subDoc r:id="rId6" xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships" />
</w:p>
<w:sectPr>
<w:headerReference w:type="default" r:id="rId7" xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships" />
<w:type w:val="continuous" />
<w:pgSz w:w="11906" w:h="16838" />
<w:pgMar w:top="1417" w:right="1417" w:bottom="1134" w:left="1417" w:header="708" w:footer="708" w:gutter="0" />
<w:cols w:space="708" />
<w:docGrid w:linePitch="360" />
</w:sectPr>
</w:body>
and the code:
public class GeneratedClass
{
// Creates an Body instance and adds its children.
public Body GenerateBody()
{
Body body1 = new Body();
Paragraph paragraph1 = new Paragraph();
ParagraphProperties paragraphProperties1 = new ParagraphProperties();
ParagraphStyleId paragraphStyleId1 = new ParagraphStyleId(){ Val = "Heading1" };
paragraphProperties1.Append(paragraphStyleId1);
SubDocumentReference subDocumentReference1 = new SubDocumentReference(){ Id = "rId6" };
paragraph1.Append(paragraphProperties1);
paragraph1.Append(subDocumentReference1);
SectionProperties sectionProperties1 = new SectionProperties();
HeaderReference headerReference1 = new HeaderReference(){ Type = HeaderFooterValues.Default, Id = "rId7" };
SectionType sectionType1 = new SectionType(){ Val = SectionMarkValues.Continuous };
PageSize pageSize1 = new PageSize(){ Width = (UInt32Value)11906U, Height = (UInt32Value)16838U };
PageMargin pageMargin1 = new PageMargin(){ Top = 1417, Right = (UInt32Value)1417U, Bottom = 1134, Left = (UInt32Value)1417U, Header = (UInt32Value)708U, Footer = (UInt32Value)708U, Gutter = (UInt32Value)0U };
Columns columns1 = new Columns(){ Space = "708" };
DocGrid docGrid1 = new DocGrid(){ LinePitch = 360 };
sectionProperties1.Append(headerReference1);
sectionProperties1.Append(sectionType1);
sectionProperties1.Append(pageSize1);
sectionProperties1.Append(pageMargin1);
sectionProperties1.Append(columns1);
sectionProperties1.Append(docGrid1);
body1.Append(paragraph1);
body1.Append(sectionProperties1);
return body1;
}
}