I am writing a Winform application in .NET 3.5, and I need unzip a .rar or .zip file.
I found many things, but I didn\'t found none 3rd party.
I couldn\'t change to .NET 4
The .NET framework doesn't support .RAR files, and didn't have support for Zip files until .NET 4.5.
If you want to support .ZIP (or .RAR) in .NET 3.5, you'll need a third party solution. The DotNetZip library, for example, supports .NET 3.5, and is fully functional for handling of .ZIP files.
There are commercial products which support RAR, such as Chilkat RAR.