Assembly: mscorlib (in mscorlib.dll)
The d parameter is a double-precision floating-point number that represents a date as the number of days before or after the base date, midnight, 30 December 1899. The sign and integral part of d encode the date as a positive or negative day displacement from 30 December 1899, and the absolute value of the fractional part of d encodes the time of day as a fraction of a day displacement from midnight. d must be a value between negative 657435.0 through positive 2958466.0.
Note that because of the way dates are encoded, there are two ways of representing any time of day on 30 December 1899. For example, -0.5 and 0.5 both mean noon on 30 December 1899 because a day displacement of plus or minus zero days from the base date is still the base date, and a half day displacement from midnight is noon.