Zip folder in C#

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

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);
}

"Where should I copy ICSharpCode.SharpZipLib.dll to see that namespace in Visual Studio?"

You need to add the dll file as a reference in your project. Right click on References in the Solution Explorer->Add Reference->Browse and then select the dll.

Finally you'll need to add it as a using statement in whatever files you want to use it in.

Following code uses a third-party ZIP component from Rebex:

// add content of the local directory C:\Data\
// to the root directory in the ZIP archive
// (ZIP archive C:\archive.zip doesn't have to exist)
Rebex.IO.Compression.ZipArchive.Add(@"C:\archive.zip", @"C:\Data\*", "");

Or if you want to add more folders without need to open and close archive multiple times:

using Rebex.IO.Compression;
...


// open the ZIP archive from an existing file
ZipArchive zip = new ZipArchive(@"C:\archive.zip", ArchiveOpenMode.OpenOrCreate);


// add first folder
zip.Add(@"c:\first\folder\*","\first\folder");


// add second folder
zip.Add(@"c:\second\folder\*","\second\folder");


// close the archive
zip.Close(ArchiveSaveAction.Auto);

You can download the ZIP component here.

Using a free, LGPL licensed SharpZipLib is a common alternative.

Disclaimer: I work for Rebex

There is a ZipPackage class in the System.IO.Packaging namespace which is built into .NET 3, 3.5, and 4.0.

http://msdn.microsoft.com/en-us/library/system.io.packaging.zippackage.aspx

Here is an example how to use it. http://www.codeproject.com/KB/files/ZipUnZipTool.aspx?display=Print

This answer changes with .NET 4.5. Creating a zip file becomes incredibly easy. No third-party libraries will be required.

string startPath = @"c:\example\start";
string zipPath = @"c:\example\result.zip";
string extractPath = @"c:\example\extract";


ZipFile.CreateFromDirectory(startPath, zipPath);
ZipFile.ExtractToDirectory(zipPath, extractPath);

ComponentPro ZIP can help you achieve that task. The following code snippet compress files and dirs in a folder. You can use wilcard mask as well.

using ComponentPro.Compression;
using ComponentPro.IO;


...


// Create a new instance.
Zip zip = new Zip();
// Create a new zip file.
zip.Create("test.zip");


zip.Add(@"D:\Temp\Abc"); // Add entire D:\Temp\Abc folder to the archive.


// Add all files and subdirectories from 'c:\test' to the archive.
zip.AddFiles(@"c:\test");
// Add all files and subdirectories from 'c:\my folder' to the archive.
zip.AddFiles(@"c:\my folder", "");
// Add all files and subdirectories from 'c:\my folder' to '22' folder within the archive.
zip.AddFiles(@"c:\my folder2", "22");
// Add all .dat files from 'c:\my folder' to '22' folder within the archive.
zip.AddFiles(@"c:\my folder2", "22", "*.dat");
// Or simply use this to add all .dat files from 'c:\my folder' to '22' folder within the archive.
zip.AddFiles(@"c:\my folder2\*.dat", "22");
// Add *.dat and *.exe files from 'c:\my folder' to '22' folder within the archive.
zip.AddFiles(@"c:\my folder2\*.dat;*.exe", "22");


TransferOptions opt = new TransferOptions();
// Donot add empty directories.
opt.CreateEmptyDirectories = false;
zip.AddFiles(@"c:\abc", "/", opt);


// Close the zip file.
zip.Close();

http://www.componentpro.com/doc/zip has more examples

In .NET 4.5 the ZipFile.CreateFromDirectory(startPath, zipPath); method does not cover a scenario where you wish to zip a number of files and sub-folders without having to put them within a folder. This is valid when you wish the unzip to put the files directly within the current folder.

This code worked for me:

public static class FileExtensions
{
public static IEnumerable<FileSystemInfo> AllFilesAndFolders(this DirectoryInfo dir)
{
foreach (var f in dir.GetFiles())
yield return f;
foreach (var d in dir.GetDirectories())
{
yield return d;
foreach (var o in AllFilesAndFolders(d))
yield return o;
}
}
}


void Test()
{
DirectoryInfo from = new DirectoryInfo(@"C:\Test");
using (var zipToOpen = new FileStream(@"Test.zip", FileMode.Create))
{
using (var archive = new ZipArchive(zipToOpen, ZipArchiveMode.Create))
{
foreach (var file in from.AllFilesAndFolders().OfType<FileInfo>())
{
var relPath = file.FullName.Substring(from.FullName.Length+1);
ZipArchiveEntry readmeEntry = archive.CreateEntryFromFile(file.FullName, relPath);
}
}
}
}

Folders don't need to be "created" in the zip-archive. The second parameter "entryName" in CreateEntryFromFile should be a relative path, and when unpacking the zip-file the directories of the relative paths will be detected and created.

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");