OpenXML MainDocumentPart.Document.Save() doesn't seem to save in .Net 5

Question

I've been porting an application from .net framework to .net 5. I'm trying to generate a word document by reading a template file, using Open-XML-PowerTools to replace some text, and saving the new version. I can't get the "Save()" to do anything: Here's some slightly simplified code which demonstrates the problem:

                byte[] content = System.IO.File.ReadAllBytes("c:\\Temp\\myrequesttemplate.docx");
                using (MemoryStream mstr = new MemoryStream())
                {
                    mstr.Write(content, 0, content.Length);
                    using var docTest = WordprocessingDocument.Open(mstr, true);
                    {
                        docTest.ReplaceText("%NAME%", mrcrequest.RequesterName); // At this point, I can see by looking at the document.innerxml that the replacement has been successful.
                        docTest.MainDocumentPart.Document.Save();
                    }
                    using (FileStream fs = new FileStream("c:\\Temp\\TestWordDoc.docx", FileMode.CreateNew))
                    {
                        mstr.WriteTo(fs);
                    }

                }

The file created is just a copy of the old file, without the replacement. I can see that the replacement succeeds using the debugger to look at the innerXML of the MainDocument. It just seems to not be writing back to the stream. I've tried using ".MainDocumentPart.PutXDocument();" instead of ".Save()" - it makes no difference.

I'm using DocumentFormat.OpenXML version 2.12, System.IO.Packaging 5.0.0, and Open-XML-PowerTools 4.4.0

Any ideas anyone? It's driving me nuts. Thanks.

Answer 1

Finally, I found it: For anyone else facing the same issue. You need to put docTest;Close(). after the;Save(). - on the old,Net Framework version it didn't need it. but in,Net core. you do.

                byte[] content = System.IO.File.ReadAllBytes("c:\\Temp\\myrequesttemplate.docx");
                using (MemoryStream mstr = new MemoryStream())
                {
                    mstr.Write(content, 0, content.Length);
                    using var docTest = WordprocessingDocument.Open(mstr, true);
                    {
                        docTest.ReplaceText("%NAME%", mrcrequest.RequesterName); // At this point, I can see by looking at the document.innerxml that the replacement has been successful.
                        docTest.MainDocumentPart.Document.Save();
                        docTest.Close();
                    }
                    using (FileStream fs = new FileStream("c:\\Temp\\TestWordDoc.docx", FileMode.CreateNew))
                    {
                        mstr.WriteTo(fs);
                    }

                }

By the way, I forgot to mention that docTest.ReplaceText is just an extension method I put in to replace text whilst preserving line breaks - that's not important.