‫فشرده سازی فایل ها در NET 4.5.

string extractPath = @"c:\example\extract";
ZipFile.ExtractToDirectory(zipPath, extractPath);

using (ZipArchive zipFile = ZipFile.Open(zipName, ZipArchiveMode.Create))
{
    zipFile.CreateEntryFromFile(@"C:\Temp\File1.txt", "File1.txt");
    zipFile.CreateEntryFromFile(@"C:\Temp\File2.txt", "File2.txt", CompressionLevel.Fastest);
}

using (MemoryStream zipStream = new MemoryStream())
{
        using (ZipArchive zipFile = new ZipArchive(zipStream, ZipArchiveMode.Create))
        {
                zipFile.CreateEntryFromFile(filepath, filename);
        }
}

using (ZipArchive archive = ZipFile.OpenRead(zipName))
{
    foreach (ZipArchiveEntry file in archive.Entries)
    {
           Console.WriteLine("File Name: {0}", file.Name);
           Console.WriteLine("File Size: {0} bytes", file.Length);
           Console.WriteLine("Compression Ratio: {0}", ((double)file.CompressedLength  / file.Length).ToString("0.0%"));
           file.ExtractToFile(directorypath);
    }
}