How do I ZIP a file in C#, using no 3rd-party APIs?

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+16 Q:

How do I ZIP a file in C#, using no 3rd-party APIs?

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

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?

+26 A:

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.

Brian Ensink 2009-06-02 16:46:50

This has worked well in the past for me.

David 2009-06-02 16:48:36

Oh SO, how I love you! Thanks Brian; yuo just saved us a lot of headaches and some $$$.

Esteban Araya 2009-06-02 16:53:03

Note that this doesn't always work in reverse. Some Zip files will not rehydrate using the ZipPackage class. Files made with ZipPackage will so you should be good.

Craig 2009-06-02 16:59:00

Glad I could help.

Brian Ensink 2009-06-02 17:02:26

+3 A:

Compress Zip files with Windows Shell API and C#

Dana Holt 2009-06-02 16:47:01

You may not want to do this with the shell API because it shows a progress box while running. There's a flag to turn off the progress box but it does not always work.

Cheeso 2009-06-02 17:03:58

@Cheeso - The article addresses that issue by moving the shell API code to a separate exe, then using .NET to run it specifying the process have a window style of hidden.

Dana Holt 2009-06-02 17:08:24

Wow... Every time i see this article linked to, i cringe. If you're worried about adding a dependency to a third-party library or .exe, then adding one to what is essentially an add-in for the Windows Shell should send you running for the hills...

Shog9 2009-06-02 17:17:11

@Shog9 - I agree it isn't something I would do, but it does meet the question's requirements. :)

Dana Holt 2009-06-02 17:18:38

Heh... that it does. Fair enough.

Shog9 2009-06-02 17:21:24

Esteban Araya 2009-06-02 20:41:45

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 Swersky 2009-06-02 16:47:08

You can use the GZipStream class to compress streams. There are lots of examples around on how to do what you want to do.

JP Alioto 2009-06-02 16:48:40

Doesn't that use GZIP, not ZIP?

grawity 2009-06-02 16:51:46

GZipStream does not read or write zip files. The doc is quite clear on this.

Cheeso 2009-06-02 16:55:44

Wrapping a compressed stream with a file stream and writing it out to a file is trivial.

JP Alioto 2009-06-02 16:57:29

Wrapping a GZipStream with a FileStream will produce a GZIP file, not a ZIP file.

Cheeso 2009-06-02 17:05:40

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

Tim 2009-06-02 16:50:15

I can't use 3rd party libs.

Esteban Araya 2009-06-02 16:53:53

Shoud have read a little more closely. Doh! SharpZipLib is still a nice library for what it's worth.

Tim 2009-06-02 17:06:55

ansaurus

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How do I ZIP a file in C#, using no 3rd-party APIs?

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