The other day I posted about a free .NET library for creating zip files on the fly:

     http://weblogs.asp.net/dneimke/archive/2005/02/23/378781.aspx

Here's a little method that I wrote which wraps the functionality of the ICSharpCode library to easily package one or more files into a zip file.

private static void WriteZipFile( string[] filesToZip, string writeToFilePath ) {

  try {
    if ( EnsureDirectory(writeToFilePath) ) {
      
      Crc32 crc = new Crc32();
      ZipOutputStream s = new ZipOutputStream(File.Create(writeToFilePath));
      s.SetLevel(9); // 0 - store only to 9 - means best compression

      for( int i=0; i<filesToZip.Length; i++ ) {
      
        // Must use a relative path here so that files show up in the Windows Zip File Viewer
        // .. hence the use of Path.GetFileName(...)
        ZipEntry entry = new ZipEntry(Path.GetFileName(filesToZip[i]));
        entry.DateTime = DateTime.Now;

        // Read in the 
        using(FileStream fs = File.OpenRead(filesToZip[i])) {
  
          byte[] buffer = new byte[fs.Length];
          fs.Read(buffer, 0, buffer.Length);

          // set Size and the crc, because the information
          // about the size and crc should be stored in the header
          // if it is not set it is automatically written in the footer.
          // (in this case size == crc == -1 in the header)
          // Some ZIP programs have problems with zip files that don't store
          // the size and crc in the header.
          entry.Size = fs.Length;
          fs.Close();
      
          crc.Reset();
          crc.Update(buffer);
          entry.Crc  = crc.Value;
          s.PutNextEntry(entry);
          s.Write(buffer, 0, buffer.Length);
        }
      }
  
      s.Finish();
      s.Close();
    }
  } 
  catch( Exception ex ) {
    HttpContext.Current.Trace.Warn( ex.ToString() ) ;
  }
}