Deleting files in C# (specifically, files within the .git folder)

I wanted to delete an entire directory so I called Directory.Delete(path, true) and all was well and everything was deleted. I then wrote some code to initialize git within said folder, which when I tried to delete using the aforementioned Directory.Delete things went pear-shaped and all was not well and nothing was deleted. After some unsuccessful google searches involving weird combinations of git, .git, delete and c#, I finally noticed that the files causing me grief were marked with the attributes RA, with R being Read-only and A being Archive. I never really checked which one was the offender but based on my experience of other OS's where read-only is (rightly) treated as something you should check before deleting (Windows Explorer just goes right ahead and deletes it, no problem), I assume read-only was the problem. Hence the following:

    private void DeleteDirectory(string d) {
        foreach (var sub in Directory.EnumerateDirectories(d)) {
        foreach (var f in Directory.EnumerateFiles(d)) {
            var fi = new FileInfo(f);
            fi.Attributes = FileAttributes.Normal;

Yay for recursion.