title: Add Files Into Existing Zip
body: <p>I can successfully extract files from a zip folder into a folder, but I am not quite sure how to take those files and add them into an existing zip file.  I extract them into a directory onto the desktop called "mod", and then I need to add them to another zip file.  Help?  Here is my extraction code- </p>
  
  <pre><code>ZipFile zip = ZipFile.Read(myZip);
  zip.ExtractAll(outputDirectory,ExtractExistingFileAction.OverwriteSilently);
  </code></pre>
  
  <p>Help is appreciated, thank you.</p>