How to remove a single Attribute (e.g. ReadOnly) from a File?

Question

Let say, a file has the following attributes: ReadOnly, Hidden, Archived, System. How can I remove only one Attribute? (for example ReadOnly)

Answer 1

string file = "file.txt";
FileAttributes attrs = File.GetAttributes(file);
if (attrs.HasFlag(FileAttributes.ReadOnly))
    File.SetAttributes(file, attrs & ~FileAttributes.ReadOnly);