Compress/Decompress Zip Files without Third-party Libraries in C#

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Introduction

This is a follow-up to the article "Compress Zip files with Windows Shell API and C#" by "Gerald Gibson Jr".

I needed a similar functionality for a very basic compression/decompression and didn't want to use any third party libraries. Out of the many options that I came up with, I thought the Windows Shell API served best for my purpose.

Granted, that this is not the best way to archive/un-archive files, but I found this to be one of the simplest ways to achieve what I needed.

Background

What I'm presenting here is a simple wrapper class for archiving/un-archiving using the Windows Shell API with (very) minimal error handling. Additionally, I've also included a function to copy the file permissions from one file to another. This might be useful in some cases.

Using the Code

As the class uses the Shell32 namespace, a reference to Microsoft Shell Controls and Automation should be added to the project. This would come under the COM references section. The wrapper class is named ArchiveManager and has a few public static methods that expose the functionalities.

public static bool Archive(string archiveFile, string unArchiveFolder);
public static bool UnArchive(string archiveFile);
public static bool UnArchive(string archiveFile, string unArchiveFolder);
public static bool CopyPermissions(string sourceFile, string destFile) ;

The method names are pretty self explanatory, however a sample console application has been included in the accompanying code which shows sample usage of the wrapper class.

string _sourceFile = "Template.zip";
if (!ArchiveManager.UnArchive(_sourceFile))
{  
   Console.WriteLine("ERROR: " + ArchiveManager.LastError);
}

Other methods can be used in a similar way.

Points of Interest

One of the issues with this approach is that the Shell32 APIs used to create/extract an archive are asynchronous. Meaning, our main thread cannot determine when the archiving/extracting methods are complete.

A rather crude approach has been used to get around this problem. I've used a wait loop that keeps sleeping till the number of items in the source folder (or zip file) and destination folder (or zip file) are equal, or, a timeout (configurable) occurs.

History

• Original post: 29 August, 2013