Question

What I’m trying to do here is see whether the element exists in the xml document, if it does exist then i want to modify the inner text of it. if it doesnt exist i would like to create it and also create the appropriate inner text for it. However, when it an element does exist and i try to change it’s inner text to something shorter than it was the whole xml files writing seems to shift.

My code:

                XmlDocument xmldoc = new XmlDocument();
                xmldoc.Load(path);
                XmlNodeList felement = xmldoc.GetElementsByTagName(Element);
                FileStream fs = new FileStream(path, FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite);
                if (felement.Count == 0)
                {
                    XmlElement elmRoot = xmldoc.DocumentElement;
                    XmlElement xmlele = xmldoc.CreateElement(Element);
                    xmlele.AppendChild(xmldoc.CreateTextNode(data));
                    elmRoot.AppendChild(xmlele);
                    xmldoc.Save(fs);
                }
                else
                {
                    felement[0].InnerText = data;
                    xmldoc.Save(fs);
                }
                fs.Close();

XML File before modifying with a shorter inner text:

<?xml version="1.0" encoding="utf-8"?>
<MyXMLFile>
  <Source>C:\Users\Dacto\Desktop\</Source>
  <Destination>C:\Program Files\Adobe</Destination>
</MyXMLFile>

After shorter inner text:

    <?xml version="1.0" encoding="utf-8"?>
<MyXMLFile>
  <Source>C:\Users\Dacto\Desktop\Napster</Source>
  <Destination>C:\Users</Destination>
</MyXMLFile>/MyXMLFile>

See the “extra” /MyXMLFile> what’s going on??

Answer 1

Since the output isn’t valid XML then it’s unlikely that XmlDocument.Save produced the entire content of the file. Given this, I’d suspect that when creating the FileStream you should supply a different parameter rather than FileMode.Open – FileMode.Create will ensure that the file is truncated before being written to – currently it’s being overwritten, leaving the old content in place if the new file isn’t large enough to cover it.