title: How to Unzip all .Zip file from Folder using C# 4.0 and without using any OpenSource Dll?
body: <p>I have a folder containing <strong>.ZIP files</strong>. Now, I want to Extract the ZIP Files to specific folders using C#, but without using any external assembly or the .Net Framework 4.5.</p>
  
  <p>I have searched, but not found any solution for unpacking *.zip files using Framework 4.0 or below.</p>
  
  <p>I tried GZipStream, but it only supports .gz and not .zip files.</p>