CODEWITHSUNDEEP
c#xml
user2913184
user2913184

Reputation: 600

Xml document gets written twice rather than overwriting through an in-memory stream

I'm trying to open an archive Xml file (inside a zip file but not extracting it to a physical directory) in an in-memory stream then making changes to it and saving it. But archive xml file doesn't get overwritten rather it gets two copies of Xml data. One copy is the original copy of Xml data and the other one is changed/modified/edited copy of Xml data in the same archive file. Here is my code, please help me overwrite the existing Xml data with the changes made rather than having 2 copies of Xml data in the same archive xml file.

static void Main(string[] args)
{
  string rootFolder =     @"C:\Temp\MvcApplication5\MvcApplication5\Package1";
  string archiveName = "MvcApplication5.zip";
  string folderFullPath = Path.GetFullPath(rootFolder);
  string archivePath = Path.Combine(folderFullPath, archiveName);
  string fileName = "archive.xml";

  using (ZipArchive zip = ZipFile.Open(archivePath, ZipArchiveMode.Update))
  {
      var archiveFile = zip.GetEntry(fileName);
      if (archiveFile == null)
      {
          throw new ArgumentException(fileName, "not found in Zip");
      }

      if (archiveFile != null)
      {
          using (Stream stream = archiveFile.Open())
          {
              XDocument doc = XDocument.Load(stream);
              IEnumerable<XElement> xElemAgent = doc.Descendants("application");
              foreach(var node in xElemAgent)
              {
                  if(node.Attribute("applicationPool").Value!=null)
                  {
                      node.Attribute("applicationPool").Value = "MyPool";
                  }
              }

              doc.Save(stream);
          }

          Console.WriteLine("Document saved");
      }
  }   
}

Upvotes: 0

Views: 626

Answers (2)

Dinerdo
Dinerdo

Reputation: 582

I came across this same issue just now, and I fixed it by adding this first line:

                        stream.SetLength(0);
                        xmlDoc.Save(stream);

edit: I see you came across the same solution as you mentioned in the comments of the previous answer. You can add an answer to your own question. It would have helped someone like me :]

Upvotes: 0

Bas
Bas

Reputation: 27095

You are first reading the XML data from the stream and then writing to the same stream, which is pointing to the end of the file. To illustrate, let's say the old file contains ABCD and we want to replace this with 123.

The current approach would result in ABCD123, since the stream is pointing to the last char in ABCD.

If you reset the stream to position 0 (stream.Seek(0) before writing the changed file, the file would contain 123D, because it wouldn't reduce the file length.

The solution is to delete your old ZipArchiveEntry and create a new one.

Upvotes: 1

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