Create normal zip file programmatically

You can now use the ZipArchive class (System.IO.Compression.ZipArchive), available from .NET 4.5

You have to add System.IO.Compression as a reference.

Example: Generating a zip of PDF files

using (var fileStream = new FileStream(@"C:\temp\temp.zip", FileMode.CreateNew))
{
    using (var archive = new ZipArchive(fileStream, ZipArchiveMode.Create, true))
    {
        foreach (var creditNumber in creditNumbers)
        {
            var pdfBytes = GeneratePdf(creditNumber);
            var fileName = "credit_" + creditNumber + ".pdf";
            var zipArchiveEntry = archive.CreateEntry(fileName, CompressionLevel.Fastest);
            using (var zipStream = zipArchiveEntry.Open())
                zipStream.Write(pdfBytes, 0, pdfBytes.Length);
            }
        }
    }
}

My 2 cents:

    using (ZipArchive archive = ZipFile.Open(zFile, ZipArchiveMode.Create))
    {
        foreach (var fPath in filePaths)
        {
            archive.CreateEntryFromFile(fPath,Path.GetFileName(fPath));
        }
    }

So Zip files could be created directly from files/dirs.

Just an update on this for anyone else who stumbles across this question.

Starting in .NET 4.5 you are able to compress a directory using System.IO.Compression into a zip file. You have to add System.IO.Compression.FileSystem as a reference as it is not referenced by default. Then you can write:

System.IO.Compression.ZipFile.CreateFromDirectory(dirPath, zipFile);

The only potential problem is that this assembly is not available for Windows Store Apps.