title: Add custom configuration Element at runtime
body: <p>Is it possible to add an custom configuration element at runtime.</p>
  
  <p>Here is my app.config file</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8" ?&gt;
  &lt;configuration&gt;
    &lt;configSections&gt;
      &lt;section name="NodeList"
                 type="Configuration.NodeListSection, NodeListConfiguration"
                 requirePermission="false" /&gt;
    &lt;/configSections&gt;
    &lt;NodeList&gt;
      &lt;nodes&gt;
        &lt;add name="Dev1" isdefault="false" description ="Dev server" /&gt;
        &lt;add name="QA1" isdefault="true" description="QA server"/&gt;
        &lt;add name="Prod1" isdefault="false" description="Production" /&gt;
      &lt;/nodes&gt;
    &lt;/NodeList&gt;
  &lt;/configuration&gt;
  </code></pre>
  
  <p>Can we add more nodes at runtime using C# code. </p>