Merge multiple word documents into one Open Xml

Question

I have around 10 word documents which I generate using open xml and other stuff. Now I would like to create another word document and one by one I would like to join them in

Answer 1

The only thing missing in these answers is the for loop.

For those who just want to copy / paste it:

void MergeInNewFile(string resultFile, IList filenames)
{
    using (WordprocessingDocument document = WordprocessingDocument.Create(resultFile, WordprocessingDocumentType.Document))
    {
        MainDocumentPart mainPart = document.AddMainDocumentPart();
        mainPart.Document = new Document(new Body());

        foreach (string filename in filenames)
        {
            AlternativeFormatImportPart chunk = mainPart.AddAlternativeFormatImportPart(AlternativeFormatImportPartType.WordprocessingML);
            string altChunkId = mainPart.GetIdOfPart(chunk);

            using (FileStream fileStream = File.Open(filename, FileMode.Open))
            {
                chunk.FeedData(fileStream);
            }

            AltChunk altChunk = new AltChunk { Id = altChunkId };
            mainPart.Document.Body.AppendChild(altChunk);
        }

        mainPart.Document.Save();
    }
}

All credits go to Chris and yonexbat