Remove readonly attribute from directory

Question

How can I programatically remove the readonly attribute from a directory in C#?

Answer 1

Using the -= assignment operator is dangerous for two reasons:
1) It works ONLY IF the ReadOnly attribute is set, thus a test is required beforehand.
2) It is performing a subtract operation, which is not is not the best choice when working with binary flags. The subtract operation works if condition 1 (above) is true, but additional subtract operations will ALTER OTHER BITS in the FileAttributes field!

Use &= ~FileAttributes.ReadOnly; to remove ReadOnly flag.

Use |= FileAttributes.ReadOnly; to apply ReadOnly flag.

Answer 2

Got it finally. ;)

class Program
{
    static void Main(string[] args)
    {
        DirectoryInfo di = new DirectoryInfo("c:\\test");

        FileAttributes f = di.Attributes;

        Console.WriteLine("Directory c:\\test has attributes:");
        DecipherAttributes(f);

    }

    public static void DecipherAttributes(FileAttributes f)
    {
        // To set use File.SetAttributes

        File.SetAttributes(@"C:\test", FileAttributes.ReadOnly);

        if ((f & FileAttributes.ReadOnly) == FileAttributes.ReadOnly)
            Console.WriteLine("ReadOnly");

        // To remove readonly use "-="
        f -= FileAttributes.ReadOnly;

        if ((f & FileAttributes.ReadOnly) == FileAttributes.ReadOnly)
            Console.WriteLine("ReadOnly");
        else
            Console.WriteLine("Not ReadOnly");
    }
}