title: How to update data store in Word docx file
body: <p>I have a Word docx file that has a customXML part to hold data that is used to populate Content Controls.
  The customXML part holds an XML file named item.xml, which is a straight and simple XML file with a Root element and some custom elements of mine.
  How do I read the XML file, change the element values and see to it the docx is updated properly?
  I can get the customXML part with</p>
  
  <pre><code>CustomXmlPart part = mainPart.CustomXmlParts.FirstOrDefault();
  </code></pre>
  
  <p>Then I have to get the contents of the item.XML from that part etc. ...</p>
  
  <p>The data binding stuff in document.xml is taken care of, btw.</p>