title: Writing data to App_Data
body: <p>I want to write a .xml file using the following code into the App_Data/posts. Why is it causing an error?</p>
  <h3>Code</h3>
  <pre><code> Stream writer  = new FileStream(&quot;..'\'App_Data'\'posts'\'&quot; + new Guid(post_ID.ToString()).ToString() + &quot;.xml&quot;, FileMode.Create);
  </code></pre>