Replace an image in word doc

Question

I have many word documents(more than 10k) which have images(logo) in them. I want to replace the logo that i have in the word doc with another image. Some of these word files may not even have images in them and some may have multiple images in them. Images are not necessarily in the header section of the doc.

I have gone through some questions on this in Stackoverflow. Mainly this one

But being new to OpenXML, I'm currently not even able to replace the images inside a single word doc. The problem I'm facing is on trying to replace an image in my word doc, it seems to work fine, but there is no change in the Word Doc whatsoever. Any help would be appreciated.

This is the code I've tried so far

byte[] docBytes = File.ReadAllBytes(_myFilePath);
using (MemoryStream ms = new MemoryStream())
{
    ms.Write(docBytes, 0, docBytes.Length);

    using (WordprocessingDocument wpdoc = WordprocessingDocument.Open(ms, true))
    {
        MainDocumentPart mainPart = wpdoc.MainDocumentPart;
        Document doc = mainPart.Document;

        IEnumerable<Drawing> drawings = mainPart.Document.Descendants<Drawing>().ToList();
    foreach (Drawing drawing in drawings)
    {
        DocProperties dpr = drawing.Descendants<DocProperties>().FirstOrDefault();
        if (dpr != null && dpr.Name == "Picture 1")
        {
            foreach (DocumentFormat.OpenXml.Drawing.Blip b in drawing.Descendants<DocumentFormat.OpenXml.Drawing.Blip>().ToList())
            {
                OpenXmlPart imagePart = wordDoc.MainDocumentPart.GetPartById(b.Embed);
                using (var writer = new BinaryWriter(imagePart.GetStream()))
                {
                    writer.Write(File.ReadAllBytes(Path to my image with which to replace));
                }
            }
        }
    }
   }
}

This produces no change in the single document i'm trying it for. Also I was wondering how this can be done for docs with multiple images in the above case I opened the xml file and saw that the filename in doc properties was "Picture 1", but for word docs with multiple images, this won't be possible. Any help will be appreciated. Thanks

Answer 1

You're not saving the document you've created. Your document is currently in a memory stream, you have to then write the memory stream to your file system and from there you can open it. You're looking for something like the following:

    byte[] docBytes = File.ReadAllBytes(_myFilePath);
    using (MemoryStream ms = new MemoryStream())
    {
        ms.Write(docBytes, 0, docBytes.Length);
        using (WordprocessingDocument wpdoc = WordprocessingDocument.Open(ms, true))
        {
            MainDocumentPart mainPart = wpdoc.MainDocumentPart;
            Document doc = mainPart.Document;
            IEnumerable<Drawing> drawings = mainPart.Document.Descendants<Drawing>().ToList();
            foreach (Drawing drawing in drawings)
            {
                DocProperties dpr = drawing.Descendants<DocProperties>().FirstOrDefault();
                if (dpr != null && dpr.Name == "Picture 1")
                {
                    foreach (DocumentFormat.OpenXml.Drawing.Blip b in drawing.Descendants<DocumentFormat.OpenXml.Drawing.Blip>().ToList())
                    {
                        OpenXmlPart imagePart = wordDoc.MainDocumentPart.GetPartById(b.Embed);
                        using (var writer = new BinaryWriter(imagePart.GetStream()))
                        {
                            writer.Write(File.ReadAllBytes(Path to my image with which to replace));
                        }
                    }
                }
            }
        }

        using (FileStream fs = new FileStream(fileName, FileMode.CreateNew, FileAccess.Write))
        {
            ms.CopyTo(fs);
        }
    }

If you think about it, you're reading in a document and storing it in your RAM. Then you manipulate it and as soon as you dispose of your memory stream, it vanishes. You have to actually write the bytes you manipulated to somewhere.