You can use the 'Date property of a DateTime value to extract only the Date, ignoring the time:
DateTime rightNow = DateTime.Now;
DateTime oneMinuteAfterRightNow = rightNow.AddMinutes(1);
Boolean isSameDate = rightNow.Date == oneMinuteAfterRightNow.Date;
See: [
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Note: in the above example if the first DateTime was at 11:59PM, then adding one minute would move the Date of the second DateTime forward by a day, and the two dates would not be identical.