อยากทราบ Code คำนวณระยะการทำงานของลูกจ้างออกมาเป็นจำนวนกี่ปีกี่เดือนอะครับ C#

public void calculateAge(System.DateTime birthDate)
{
	Int16 mySpan = Convert.ToInt32(System.DateTime.Now.Subtract(birthDate).TotalDays);
	Int16 nowYear = System.DateTime.Now.Year;
	Int16 nowMonth = System.DateTime.Now.Month;
	Int16 birthYear = birthDate.Year;
	Int16 birthMonth = birthDate.Month;

	Int16 yearCount = default(Int16);
	for (yearCount = System.DateTime.Now.Year; yearCount >= birthYear; yearCount += -1) {
		if (yearCount % 4 == 0) {
			switch (true) {
				case yearCount == nowYear & nowMonth < 3:
					break;
				//This is a leap year but we're not past Feb yet
				//Do nothing
				case yearCount == birthYear & birthMonth > 2:
					break;
				//They were born after Feb in a leap year
				//Do nothing
				default:
					//This was a full leap year, subtract a day to make it 365
					mySpan -= 1;
					break;
			}
		}
	}

	Int16 myYears = mySpan / 365;
	Int16 myDays = mySpan - (myYears * 365);
	if (myDays < 0) {
		myYears -= 1;
		myDays = 365 + myDays;
		// myDays is negative so this will subtract
	}

	MessageBox.Show("You are " + myYears + " years and " + myDays + " days old.");
}

DateTime dob = default(DateTime);
dob = new DateTime(DateTimePicker1.Value.Year, DateTimePicker1.Value.Month, DateTimePicker1.Value.Day);
TimeSpan tday = DateTime.Now.Subtract(dob);
int years = 0;
int months = 0;
int days = 0;
months = 12 * (DateTime.Now.Year - dob.Year) + (DateTime.Now.Month - dob.Month);

if (DateTime.Now.Day < dob.Day) {
	months -= 1;
	days = DateTime.DaysInMonth(dob.Year, dob.Month) - dob.Day + DateTime.Now.Day;
} else {
	days = DateTime.Now.Day - dob.Day;
}
years = Math.Floor(months / 12);
months -= years * 12;
Interaction.MsgBox("Your age as on " + Strings.Format(Now, "dd-MMM-yyyy") + Constants.vbCrLf + years + " Years, " + months + " Months and " + days + " Days");