Maybe the main problem is, that C#'s DateTime class does not offer a direct method to subtract a DateTime from a DateTime.
This is one particular attempt I have seen these days (trying to debug some age related calculation):
- Given are birthdate A and reference date B
- let integer C be B.Year - A.Year
- decrease C by one based on some strange 3-line formula doing something with A.month, A.day, B.month and B.day
... This may work if the Dates A and B are accidently chosen correctly but basically what happend in most cases I tested this calculation with resulted in an age beeing 1 year lower than it actually was.
So, if you ever have to determine the age of someone based on a reference date, just use the maybe simplest approach to solve this problem using an extension to DateTime:
public static class DateTimeExtensions
{
public static int GetAge(this DateTime birthdate, DateTime referencedate)
{
DateTime x = referencedate.AddTicks(-1 * birthdate.Ticks);
return x.Year;
}
}
That way if you want to know someones Age based on a reference date... as in, how old will Person X (born July 4th, 1950) be at January, 1st 2012 you can do
int age = new DateTime(1950,7,4).GetAge(new DateTime(2012,1,1));
"Maybe the main problem is, that C#'s DateTime class does not offer a direct method to subtract a DateTime from a DateTime."
ReplyDeleteThis statement is incorrect. It is possible to subtract DateTime(s) in C#.
DateTime date1 = new DateTime(1950, 7, 4);
DateTime date2 = new DateTime(2012, 1, 1);
TimeSpan diff = date2.Subtract(date1);
DateTime date0 = new DateTime().Add(diff);
int yearsOld = date0.Year - 1; // to account for the min DateTime() of 1/1/0001
http://msdn.microsoft.com/en-us/library/8ysw4sby.aspx
Yes, I know that you can ".Subtract(DateTime)" from a DateTime. But by my statement I explicitly pointed out, that there is no DIRECT method to get to the result. With direct method I mean that you can't just say date1.subtract(date2).Year... Subtracting a DateTime always returns a TimeSpan, so you always end up creating a new DateTime with which you can work.
Delete