DateDiff() function in C#

By Fons Sonnemans, posted on 11-Feb-2004
5 Comments

I have written the following DateDiff() function in C#. VB.NET users already had it using the Micrsoft.VisualBasic.dll assembly. Now you can use it without referencing this 'ugly' extra assembly.

using System;


namespace ReflectionIT.System {

   &nbsppublicenum DateInterval {
   &nbsp   &nbspYear,
   &nbsp   &nbspMonth,
   &nbsp   &nbspWeekday,
   &nbsp   &nbspDay,
   &nbsp   &nbspHour,
   &nbsp   &nbspMinute,
   &nbsp   &nbspSecond
   &nbsp}

   &nbsppublicclass DateTimeUtil {

   &nbsp   &nbsppublicstaticlong DateDiff(DateInterval interval, DateTime date1, DateTime date2){

   &nbsp   &nbsp   &nbspTimeSpan ts=date2-date1;

   &nbsp   &nbsp   &nbspswitch(interval){
   &nbsp   &nbsp   &nbsp   &nbspcase DateInterval.Year:
   &nbsp   &nbsp   &nbsp   &nbsp   &nbspreturndate2.Year -date1.Year;
   &nbsp   &nbsp   &nbsp   &nbspcase DateInterval.Month:
   &nbsp   &nbsp   &nbsp   &nbsp   &nbspreturn(date2.Month -date1.Month)+(12*(date2.Year -date1.Year));
   &nbsp   &nbsp   &nbsp   &nbspcase DateInterval.Weekday:
   &nbsp   &nbsp   &nbsp   &nbsp   &nbspreturn Fix(ts.TotalDays)/7;
   &nbsp   &nbsp   &nbsp   &nbspcase DateInterval.Day:
   &nbsp   &nbsp   &nbsp   &nbsp   &nbspreturn Fix(ts.TotalDays);
   &nbsp   &nbsp   &nbsp   &nbspcase DateInterval.Hour:
   &nbsp   &nbsp   &nbsp   &nbsp   &nbspreturn Fix(ts.TotalHours);
   &nbsp   &nbsp   &nbsp   &nbspcase DateInterval.Minute:
   &nbsp   &nbsp   &nbsp   &nbsp   &nbspreturn Fix(ts.TotalMinutes);
   &nbsp   &nbsp   &nbsp   &nbspdefault:
   &nbsp   &nbsp   &nbsp   &nbsp   &nbspreturn Fix(ts.TotalSeconds);
   &nbsp   &nbsp   &nbsp}
   &nbsp   &nbsp}

   &nbsp   &nbspprivatestaticlong Fix(double Number){
   &nbsp   &nbsp   &nbspif(Number >=0){
   &nbsp   &nbsp   &nbsp   &nbspreturn(long)Math.Floor(Number);
   &nbsp   &nbsp   &nbsp}
   &nbsp   &nbsp   &nbspreturn(long)Math.Ceiling(Number);
   &nbsp   &nbsp}
   &nbsp}
}


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Blog comments

Raj

06-May-2013 8:48
If you want the exact DateDiff function as it works in SQL, you can remove time stamp of the Date variables and then Subtract one from another. It will give u exact number of days. Ex. DateTime dt = DateTime.Parse(fromDate.ToShortDateString()); DateTime dt1 = DateTime.Parse(toDate.ToShortDateString()); int noOfDays = dt.Subtract(dt1).TotalDays;

Marco Pellicciotta

13-Nov-2013 4:35
Exactly what I was looking for. Thanks!

Marco Pellicciotta

13-Nov-2013 4:46
The trick is with month values, because TimeSpan do not give you the difference of months.

Marco Pellicciotta

30-Jan-2014 8:32
Marco Pellicciotta: After using it a few times a see a bug and I want to report. The fix function must be: private static long Fix(double Number) { if (Number >= 0) { return (long)Math.Ceiling(Number); } return (long)Math.Floor(Number); } } Just change Ceiling by Floor.