title: Serialize only a part of xml file and save it
body: <p>I have a problem with respect to XML Serialization. I shall try to explain it with the following example xml file</p>
  
  <pre><code>&lt;AutoExpo&gt;
    &lt;Details&gt;
      &lt;Venue&gt;XYZ&lt;/Venue&gt;
      &lt;StartTime&gt;09:00&lt;/StartTime&gt;
      &lt;EndTime&gt;21:00&lt;/EndTime&gt;
    &lt;/Details&gt;
  
    &lt;Cars&gt;
        &lt;Car&gt;
          &lt;Company&gt;Chevrolet&lt;/Company&gt;
          &lt;Model&gt;Cruz&lt;/Model&gt;
          &lt;Color&gt;Red&lt;/Color&gt;
        &lt;/Car&gt;
  
        &lt;Car&gt;
          &lt;Company&gt;Ford&lt;/Company&gt;
          &lt;Model&gt;Fiesta&lt;/Model&gt;
          &lt;Color&gt;Blue&lt;/Color&gt;
        &lt;/Car&gt;
  
    &lt;/Cars&gt;
  &lt;/AutoExpo&gt;
  </code></pre>
  
  <p>Now, when I read this xml file, I deserialize the cars into objects. The car list can be huge. My code uses this objects and can change the properties of some cars. Now what if I want to serialize only those car objects whose properties have changed, back to the xml file and save it so that next time when my code starts it gets the latest state information. </p>