删除非空目录下所有文件

    private void DeleteFiles(string dir)
    {
        DirectoryInfo di = new DirectoryInfo(dir);
        if (di.GetDirectories().Length == 0 && di.GetFiles().Length == 0) return;
        foreach (DirectoryInfo d in di.GetDirectories())
        {
            DeleteFiles(d.FullName);
        }
        foreach (FileInfo fi in di.GetFiles())
        {
            fi.Delete();
        }
        di.Delete();
    }