static public string ToHoursMinutesSecondsMillisecondsString(this Duration item) { int hours; int minutes; int seconds; int milliseconds; item.GetHoursMinutesSecondsMilliseconds(out hours, out minutes, out seconds, out milliseconds); return(hours + ":" + minutes.ToString("D2") + ":" + seconds.ToString("D2") + "." + milliseconds.ToString("D3")); }