Zip files created with System.IO.Compression won't show directories on Mac

Question

I'm creating a zip file containing the following structure:

readme.html
my-directory\\foo.txt

var zip = new ZipArchive(...);
zip.CreateEntryFromFile("c:\\readme.html", "readme.html");
zip.CreateEntryFromFile("c:\\foo.txt", "my-directory\\foo.txt");

This creates a zip file that works fine on Windows:

However, if I open the zip file on Mac, there is no my-directory folder. Instead, foo.txt has a name of my-directory\\foo.txt :

How can I add a directory to a zip file, such that the directory shows up in the zip on Mac?

Answer 1

For better portability, I suggest you to use the Path class in c# to form your paths, like this:

string root = @"c:\"; // different mount point if in mac

zip.CreateEntryFromFile(Path.Combine(root, "readme.html"), "readme.html");
zip.CreateEntryFromFile(Path.Combine(root, "my-directory", "foo.txt"), Path.Combine("my-directory", "foo.txt"));

Answer 2

Turns out, I had forgotten that directory separators are different between Windows and Mac. 😳

The fix was creating directories by using the "/" character, which works on both Windows and Mac:

zip.CreateEntryFromFile("c:\\foo.txt", "my-directory/foo.txt");