• How To Unzip A Downloaded File
• C# Unzip File To Folder
• Zip And Unzip File Using C#

I'm pretty sure this is not a duplicate so bear with me for just a minute.

I am testing a program that downloads a zipped directory that contains text files. I tried writing a utility that unzips the directory in c# but the version of C# does not support System.IO.Compression.ZipFile. I would like to be able to unzip the files to read and compare. Is there a way to read the zipped files.

How can I programatically (C#) ZIP a file (in Windows) without using any third party libraries? I need a native windows call or something like that; I really dislike the idea of starting a process, but I will if I absolutely have to. A PInovke call would be much better.

Failing that, let me tell you what I'm really trying to accomplish: I need the ability to let a user download a collection of documents in a single request. Any ideas on how to accomplish this?

CheesoEsteban ArayaEsteban Araya

8 Answers

Are you using .NET 3.5? You could use the ZipPackage class and related classes. Its more than just zipping up a file list because it wants a MIME type for each file you add. It might do what you want.

I'm currently using these classes for a similar problem to archive several related files into a single file for download. We use a file extension to associate the download file with our desktop app. One small problem we ran into was that its not possible to just use a third-party tool like 7-zip to create the zip files because the client side code can't open it -- ZipPackage adds a hidden file describing the content type of each component file and cannot open a zip file if that content type file is missing.

adrianbanksBrian EnsinkBrian Ensink

How can I programatically (C#) ZIP a file (in Windows) without using any third party libraries?

If using the 4.5+ Framework, there is now the ZipArchive and ZipFile classes.

Yves larock rise up lyrics. You need to add references to:

• System.IO.Compression
• System.IO.Compression.FileSystem

For .NET Core targeting net46, you need to add dependencies for

• System.IO.Compression
• System.IO.Compression.ZipFile

Example project.json:

For .NET Core 2.0, just adding a simple using statement is all that is needed:

• using System.IO.Compression;

GalacticJelloGalacticJello

I was in the same situation, wanting to .NET instead of a third party library. As another poster mentioned above, simply using the ZipPackage class (introduced in .NET 3.5) is not quite enough. There is an additional file that MUST be included in the archive in order for the ZipPackage to work. If this file is added, then the resulting ZIP package can be opened directly from Windows Explorer - no problem.

All you have to do is add the [Content_Types].xml file to the root of the archive with a 'Default' node for every file extension you wish to include. Once added, I could browse the package from Windows Explorer or programmatically decompress and read its contents.

How To Unzip A Downloaded File

More information on the [Content_Types].xml file can be found here: http://msdn.microsoft.com/en-us/magazine/cc163372.aspx

Here is a sample of the [Content_Types].xml (must be named exactly) file:

And the C# for creating a ZIP file:

Note:

• This code uses the Stream.CopyTo method in .NET 4.0
• This will become much simpler with the introduction of the ZipArchive class in .NET 4.5: http://msdn.microsoft.com/en-us/library/system.io.compression.ziparchive(v=vs.110).aspx

FLICKERFLICKER

For a .NET 2.0 app I used SharpZipLib. Easy to use and open source.

Tim ScarboroughTim Scarborough

Based off Simon McKenzie's answer to this question, I'd suggest using a pair of methods like this:

Looks like Windows might just let you do this..

Unfortunately I don't think you're going to get around starting a separate process unless you go to a third party component.

Dave SwerskyDave Swersky

Add these 4 functions to your project:

And use them like this:

C# Unzip File To Folder

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Code Reference / Zip Samples

How to use SharpZipLib to work with Zip files

These samples try to cover the range of situations you will encounter.You may need to combine parts of each sample for your application.

General usage

• Unpack a zip using ZipInputStream (eg for Unseekable input streams)

Specific usage

Create a Zip from a HTML string (C#)