title: Update and Add new Tag inside XML
body: <p>Below is example of my XML:</p>
  
  <pre><code>&lt;Customers&gt;
    &lt;Customer Id="1" Name="abc"/&gt;
    &lt;Customer Id="2" Name="efg"/&gt;
  &lt;/Customers&gt;
  </code></pre>
  
  <p>How to update inside this XML using XElement?</p>
  
  <pre><code>&lt;Customer Id="1" Name="aaabbbccc"/&gt;
  </code></pre>
  
  <p>And How to add new row inside this xml??</p>
  
  <pre><code>&lt;Customers&gt;
    &lt;Customer Id="1" Name="abc"/&gt;
    &lt;Customer Id="2" Name="efg"/&gt;
    &lt;Customer Id="3" Name="test"/&gt;
  &lt;/Customers&gt;
  </code></pre>
  
  <p>And, how to get specfied name?
  For e.g, if 1 then abc, if 2 then efg</p>
  
  <p>Sorry but I have no idea, new to XML and XElement.</p>