DateTime.Now.Day.ToString("00");
DateTime.Now.ToString("dd");

DateTime.Now.Day.ToString("00");

if(DateTime.Now.Day < 10)
     return "0" + DateTime.Now.Day.ToString();
else return DateTime.Now.Day.ToString();

DateTime.Now.Day.ToString("D2")

DateTime.Now.ToString("dd");

DateTime currentDate = DateTime.Now;

// use the current date/time to configure the output directory
String dateTime = String.Format( "{0}\{0:yyyy-MM-dd}", currentDate );