Format A TimeSpan With Years

Question

I have a class with 2 date properties: FirstDay and LastDay. LastDay is nullable. I would like to generate a string in the format of

Answer 1

I think this should work:

public static int DiffYears(DateTime dateValue1, DateTime dateValue2)
{
    var intToCompare1 = Convert.ToInt32(dateValue1.ToString("yyyyMMdd"));
    var intToCompare2 = Convert.ToInt32(dateValue2.ToString("yyyyMMdd"));
    return (intToCompare2 - intToCompare1) / 10000;
}