title: I didn't find "ZipFile" class in the "System.IO.Compression" namespace
body: <p>I can't use "Zipfile" class in the name space "System.IO.Compression" my code is :</p>
  
  <pre><code>using System;
  using System.IO;
  using System.IO.Compression;
  
  namespace ConsoleApplication
  {
      class Program
      {
          static void Main(string[] args)
          {
              string startPath = @"c:\example\start";
              string zipPath = @"c:\example\result.zip";
              string extractPath = @"c:\example\extract";
  
              ZipFile.CreateFromDirectory(startPath, zipPath, CompressionLevel.Fastest,true);
  
              ZipFile.ExtractToDirectory(zipPath, extractPath);
          }
      }
  }
  </code></pre>
  
  <p>the error is :</p>
  
  <p>The name 'zipfile' does not exist in the current context</p>
  
  <p>How I can solve it ?</p>