/// <summary>
  /// Add a folder along with its subfolders to a Package
  /// </summary>
  /// <param name="folderName">The folder to add</param>
  /// <param name="compressedFileName">The package to create</param>
  /// <param name="overrideExisting">Override exsisitng files</param>
  /// <returns></returns>
  static bool PackageFolder(string folderName, string compressedFileName, bool overrideExisting)
  {
   if (folderName.EndsWith(@"\"))
    folderName = folderName.Remove(folderName.Length - 1);
   bool result = false;
   if (!Directory.Exists(folderName))
   {
    return result;
   }

   if (!overrideExisting && File.Exists(compressedFileName))
   {
    return result;
   }
   try
   {
    using (Package package = Package.Open(compressedFileName, FileMode.Create))
    {
     var fileList = Directory.EnumerateFiles(folderName, "*", SearchOption.AllDirectories);
     foreach (string fileName in fileList)
     {
      
      //The path in the package is all of the subfolders after folderName
      string pathInPackage;
      pathInPackage = Path.GetDirectoryName(fileName).Replace(folderName, string.Empty) + "/" + Path.GetFileName(fileName);

      Uri partUriDocument = PackUriHelper.CreatePartUri(new Uri(pathInPackage, UriKind.Relative));
      PackagePart packagePartDocument = package.CreatePart(partUriDocument,"", CompressionOption.Maximum);
      using (FileStream fileStream = new FileStream(fileName, FileMode.Open, FileAccess.Read))
      {
       fileStream.CopyTo(packagePartDocument.GetStream());
      }
     }
    }
    result = true;
   }
   catch (Exception e)
   {
    throw new Exception("Error zipping folder " + folderName, e);
   }
   
   return result;
  }

 /// <summary>
  /// Compress a file into a ZIP archive as the container store
  /// </summary>
  /// <param name="fileName">The file to compress</param>
  /// <param name="compressedFileName">The archive file</param>
  /// <param name="overrideExisting">override existing file</param>
  /// <returns></returns>
  static bool PackageFile(string fileName, string compressedFileName, bool overrideExisting)
  {
   bool result = false;

   if (!File.Exists(fileName))
   {
    return result;
   }

   if (!overrideExisting && File.Exists(compressedFileName))
   {
    return result;
   }

   try
   {
    Uri partUriDocument = PackUriHelper.CreatePartUri(new Uri(Path.GetFileName(fileName), UriKind.Relative));
    
    using (Package package = Package.Open(compressedFileName, FileMode.OpenOrCreate))
    {
     if (package.PartExists(partUriDocument))
     {
      package.DeletePart(partUriDocument);
     }

     PackagePart packagePartDocument = package.CreatePart(partUriDocument, "", CompressionOption.Maximum);
     using (FileStream fileStream = new FileStream(fileName, FileMode.Open, FileAccess.Read))
     {
      fileStream.CopyTo(packagePartDocument.GetStream());
     }
    }
    result = true;
   }
   catch (Exception e)
   {
    throw new Exception("Error zipping file " + fileName, e);
   }
   
   return result;
  }

/// <summary>
  /// Extract a container Zip. NOTE: container must be created as Open Packaging Conventions (OPC) specification
  /// </summary>
  /// <param name="folderName">The folder to extract the package to</param>
  /// <param name="compressedFileName">The package file</param>
  /// <param name="overrideExisting">override existing files</param>
  /// <returns></returns>
  static bool UncompressFile(string folderName, string compressedFileName, bool overrideExisting)
  {
   bool result = false;
   try
   {
    if (!File.Exists(compressedFileName))
    {
     return result;
    }

    DirectoryInfo directoryInfo = new DirectoryInfo(folderName);
    if (!directoryInfo.Exists)
     directoryInfo.Create();

    using (Package package = Package.Open(compressedFileName, FileMode.Open, FileAccess.Read))
    {
     foreach (PackagePart packagePart in package.GetParts())
     {
      ExtractPart(packagePart, folderName, overrideExisting);
     }
    }

    result = true;
   }
   catch (Exception e)
   {
    throw new Exception("Error unzipping file " + compressedFileName, e);
   }
   
   return result;
  }

  static void ExtractPart(PackagePart packagePart, string targetDirectory, bool overrideExisting)
  {
   string stringPart = targetDirectory + HttpUtility.UrlDecode(packagePart.Uri.ToString()).Replace('\\', '/');

   if (!Directory.Exists(Path.GetDirectoryName(stringPart)))
    Directory.CreateDirectory(Path.GetDirectoryName(stringPart));

   if (!overrideExisting && File.Exists(stringPart))
    return;
   using (FileStream fileStream = new FileStream(stringPart, FileMode.Create))
   {
    packagePart.GetStream().CopyTo(fileStream);
   }
  }

  <?xml version="1.0" encoding="utf-8" ?> 
<Types xmlns="http://schemas.openxmlformats.org/package/2006/content-types">
 <Default Extension="vsixmanifest" ContentType="text/xml" /> 
 <Default Extension="dll" ContentType="application/octet-stream" /> 
 <Default Extension="png" ContentType="application/octet-stream" /> 
 <Default Extension="txt" ContentType="text/plain" /> 
 <Default Extension="pkgdef" ContentType="text/plain" /> 
</Types>

 public static void Zip(string SrcFile, string DstFile, int BufferSize)
{
 FileStream fileStreamIn = new FileStream
 (SrcFile, FileMode.Open, FileAccess.Read);
 FileStream fileStreamOut = new FileStream
 (DstFile, FileMode.Create, FileAccess.Write);
 ZipOutputStream zipOutStream = new ZipOutputStream(fileStreamOut);
 byte[] buffer = new byte<buffersize />;
 ZipEntry entry = new ZipEntry(Path.GetFileName(SrcFile));
 zipOutStream.PutNextEntry(entry);
 int size;
 do
 {
  size = fileStreamIn.Read(buffer, 0, buffer.Length);
  zipOutStream.Write(buffer, 0, size);
 } while (size > 0);
 zipOutStream.Close();
 fileStreamOut.Close();
 fileStreamIn.Close();
}

  public static void UnZip(string SrcFile, string DstFile, int BufferSize)
{
 FileStream fileStreamIn = new FileStream
 (SrcFile, FileMode.Open, FileAccess.Read);
 ZipInputStream zipInStream = new ZipInputStream(fileStreamIn);
 ZipEntry entry = zipInStream.GetNextEntry();
 FileStream fileStreamOut = new FileStream
 (DstFile + @"\" + entry.Name, FileMode.Create, FileAccess.Write);
 int size;
 byte[] buffer = new byte<buffersize />;
 do
 {
  size = zipInStream.Read(buffer, 0, buffer.Length);
  fileStreamOut.Write(buffer, 0, size);
 } while (size > 0);
 zipInStream.Close();
 fileStreamOut.Close();
 fileStreamIn.Close();
}

  using (ZipFile zip = new ZipFile())
 {
 zip.AddFile("ReadMe.txt");
 zip.AddFile("7440-N49th.png");
 zip.AddFile("2008_Annual_Report.pdf");  
 zip.Save("Archive.zip");
 }

 private void MyExtract()
 {
  string zipToUnpack = "C1P3SML.zip";
  string unpackDirectory = "Extracted Files";
  using (ZipFile zip1 = ZipFile.Read(zipToUnpack))
  {
   // here, we extract every entry, but we could extract conditionally
   // based on entry name, size, date, checkbox status, etc. 
   foreach (ZipEntry e in zip1)
   {
   e.Extract(unpackDirectory, ExtractExistingFileAction.OverwriteSilently);
   }
  }
 }

 static void Main(string[] args)
  {
   string ZipPath = @"c:\users\exampleuser\start.zip";
   string ExtractPath = @"c:\users\exampleuser\extract";
   string NewFile = @"c:\users\exampleuser\NewFile.txt";

   using (ZipArchive Archive = ZipFile.Open(ZipPath, ZipArchiveMode.Update))
   {
    Archive.CreateEntryFromFile(NewFile, "NewEntry.txt");
    Archive.ExtractToDirectory(ExtractPath);
   } 
  }