Fastest way to add new node to end of an xml?

Question

I have a large xml file (approx. 10 MB) in following simple structure:

   .......
   .......         


        

Answer 1

You need to use the XML inclusion technique.

Your error.xml (doesn't change, just a stub. Used by XML parsers to read):

]>

&logrows;

Your errorrows.txt file (changes, the xml parser doesn't understand it):

....
....
....

Then, to add an entry to errorrows.txt:

using (StreamWriter sw = File.AppendText("logerrors.txt"))
{
    XmlTextWriter xtw = new XmlTextWriter(sw);

    xtw.WriteStartElement("Error");
    // ... write error messge here
    xtw.Close();
}

Or you can even use .NET 3.5 XElement, and append the text to the StreamWriter:

using (StreamWriter sw = File.AppendText("logerrors.txt"))
{
    XElement element = new XElement("Error");
    // ... write error messge here
    sw.WriteLine(element.ToString());
}

See also Microsoft's article Efficient Techniques for Modifying Large XML Files