删除一个altChunk

Question

How can I successfully delete an altChunk with a given id from a document. The process that I'm following is -

MainDocumentPart mainPart = theDoc.MainDocumentPart;
mainPart.DeletePart(mainPart.GetPartById("AltChunkIdA1"));

I'm adding the altChunk after a given sdt. For adding an altChunk, I've the following code -

string altSchedChunkId = "AltChunkIdA1";
AlternativeFormatImportPart schedChunk = mainPart.AddAlternativeFormatImportPart(AlternativeFormatImportPartType.WordprocessingML, altSchedChunkId);
schedChunk.FeedData(File.Open(FileA12, FileMode.Open));
            AltChunk altSchedChunk = new AltChunk();
            altSchedChunk.Id = altSchedChunkId;

            OpenXmlElement parent = sdtRunSchedTerms.Parent;
            parent.InsertAfter(altSchedChunk, sdtRunSchedTerms);

But it doesn't seem to work out. Instead of the altChunk getting deleted, a new altChunk with the same id is added every time I try editing the document.

Thanks in advance,

Neha

Answer 1

I had the same issue with chunks, but I think I solved it.

If you look carefully at the code to add a chunk, you see that it actually does two things:

1. create a chunk ( AddAlternativeFormatImportPart )

and

2. add a reference to the chunck somewhere in the document ( InsertAfter ).

The code in which you delete the chunk does not delete the reference to the chunk. If you then add a new chunk with the same id and add a reference, you will end up with your chunk appearing twice.

See AltChunk class documentation on MSDN for more details.

I use this code to remove any existing references to a chunk.

var altChunks = mainPart.RootElement.Descendants<AltChunk>().Where(e => e.Id == altChunkId);

foreach (var altChunk in altChunks)
{
    altChunk.Remove();
}

After that, you can use DeletePart() to delete the chunk itself.

I must admit that I found this by trial and error, so I am not 100% sure it is the recommended way to do it, but it appears to work.

To get a better feeling about what a chunk actually is, I unzipped a .docx-file ( 7-zip is willing to do this) and found a directory word which contains chunks, as well as a directory _rels with a file document.xml.rels inside. The latter lists the references to the chuncks, ie where they should be inserted.