Question

I have an XML file that is constantly being appended to. I need to read in the data from the XML repeatedly, but on each pass I do not want to retrieve data that I have processed in the previous run.

Since I know how long the file is at the time of processing, I figure I could use the length of the file (minus the ending /Contacts tag) to determine where I last left off. Knowing this, what is the best way to retrieve all of the Contact tags starting from a particular byte position within the file?

<?xml version="1.0"?>
<Contacts>
    <Contact>
      <Name>Todd</Name>
      <Email>[e-mail]</Email>
  </Contact>
    <Contact>
      <Name>Sarah</Name>
      <Email>[e-mail]</Email>
  </Contact>
</Contacts>

This block of code grabs all of the contacts. I would like to limit it so it only picks up data after the first contact (at byte 116.)

var xdoc = XDocument.Load(PATH_TO_FILE);
var contact = xdoc.Descendants("Contact").Select(x => (string)x).ToArray();

Answer 1

I found a way to save/retrieve by index position. This will work just as well.

int position = 1;
var contacts = xdoc
    .Descendants("Contact")
    .Select((x, index) => new { Contact = x, Index = index })
    .Where(x => x.Index >= position)
    .Select(x => x.Contact);