Zip folder in C#

From the DotNetZip help file, http://dotnetzip.codeplex.com/releases/

using (ZipFile zip = new ZipFile())
{
   zip.UseUnicodeAsNecessary= true;  // utf-8
   zip.AddDirectory(@"MyDocuments\ProjectX");
   zip.Comment = "This zip was created at " + System.DateTime.Now.ToString("G") ; 
   zip.Save(pathToSaveZipFile);
}

There's nothing in the BCL to do this for you, but there are two great libraries for .NET which do support the functionality.

• SharpZipLib
• DotNetZip

I've used both and can say that the two are very complete and have well-designed APIs, so it's mainly a matter of personal preference.

I'm not sure whether they explicitly support adding Folders rather than just individual files to zip files, but it should be quite easy to create something that recursively iterated over a directory and its sub-directories using the DirectoryInfo and FileInfo classes.

There's an article over on MSDN that has a sample application for zipping and unzipping files and folders purely in C#. I've been using some of the classes in that successfully for a long time. The code is released under the Microsoft Permissive License, if you need to know that sort of thing.

EDIT: Thanks to Cheeso for pointing out that I'm a bit behind the times. The MSDN example I pointed to is in fact using DotNetZip and is really very fully-featured these days. Based on my experience of a previous version of this I'd happily recommend it.

SharpZipLib is also quite a mature library and is highly rated by people, and is available under the GPL license. It really depends on your zipping needs and how you view the license terms for each of them.

Rich

using DotNetZip (available as nuget package):

public void Zip(string source, string destination)
{
    using (ZipFile zip = new ZipFile
    {
        CompressionLevel = CompressionLevel.BestCompression
    })
    {
        var files = Directory.GetFiles(source, "*",
            SearchOption.AllDirectories).
            Where(f => Path.GetExtension(f).
                ToLowerInvariant() != ".zip").ToArray();

        foreach (var f in files)
        {
            zip.AddFile(f, GetCleanFolderName(source, f));
        }

        var destinationFilename = destination;

        if (Directory.Exists(destination) && !destination.EndsWith(".zip"))
        {
            destinationFilename += $"\\{new DirectoryInfo(source).Name}-{DateTime.Now:yyyy-MM-dd-HH-mm-ss-ffffff}.zip";
        }

        zip.Save(destinationFilename);
    }
}

private string GetCleanFolderName(string source, string filepath)
{
    if (string.IsNullOrWhiteSpace(filepath))
    {
        return string.Empty;
    }

    var result = filepath.Substring(source.Length);

    if (result.StartsWith("\\"))
    {
        result = result.Substring(1);
    }

    result = result.Substring(0, result.Length - new FileInfo(filepath).Name.Length);

    return result;
}

Usage:

Zip(@"c:\somefolder\subfolder\source", @"c:\somefolder2\subfolder2\dest");

Or

Zip(@"c:\somefolder\subfolder\source", @"c:\somefolder2\subfolder2\dest\output.zip");