DateDiff in c#(转载:DateDiff 方法在C#中的实现）

public    enum  DateInterval
{
    Second, Minute, Hour, Day, Week, Month, Quarter, Year
}

public   sealed   class  DateTimeManger
{

     private  DateTimeManger()
    {} // end of default constructor

     public   static   long  DateDiff(DateInterval Interval, System.DateTime StartDate,    System.DateTime EndDate )
    {
         long  lngDateDiffValue  =   0 ;
        System.TimeSpan TS  =   new  System.TimeSpan(EndDate.Ticks  -  StartDate.Ticks);
         switch  (Interval)
        {
             case  DateInterval.Second:
            lngDateDiffValue  =  ( long ) TS.TotalSeconds;
             break ;
             case  DateInterval.Minute:
            lngDateDiffValue  =  ( long ) TS.TotalMinutes;
             break ;
             case  DateInterval.Hour:
            lngDateDiffValue  =  ( long )TS.TotalHours;
             break ;                                    
             case  DateInterval.Day:
            lngDateDiffValue  =  ( long ) TS.Days;
             break ;
             case  DateInterval.Week:
            lngDateDiffValue  =  ( long )( TS.Days  /   7 );
             break ;
             case  DateInterval.Month:
            lngDateDiffValue  =  ( long )( TS.Days  /   30 );
             break ;
             case  DateInterval.Quarter:
            lngDateDiffValue  =  ( long )( (TS.Days  /   30 )  /   3  );
             break ;
             case  DateInterval.Year:
            lngDateDiffValue  =  ( long )( TS.Days  /   365 );
             break ;
        }
         return  (lngDateDiffValue);
    } // end of DateDiff

} // end of class

Samples:

public   class  DateDiffCS
{
     public   static   void  Main ( string [] CmdLineArgs)
    {
        System.DateTime date1  =  System.DateTime.Now;
        System.DateTime date2  =  System.DateTime.Now.AddYears( 2 );

        System.Console.Out.WriteLine( " Days :  "   +  DateTimeManger.DateDiff
        (DateTimeManger.DateInterval.Day,date1,date2).ToString());
        System.Console.Out.WriteLine( " Hours :  "   +  DateTimeManger.DateDiff
        (DateTimeManger.DateInterval.Hour,date1,date2).ToString());
        System.Console.Out.WriteLine( " Minutes :  "   +  DateTimeManger.DateDiff
        (DateTimeManger.DateInterval.Minute,date1,date2).ToString());
        System.Console.Out.WriteLine( " Month :  "   +  DateTimeManger.DateDiff
        (DateTimeManger.DateInterval.Month,date1,date2).ToString());
        System.Console.Out.WriteLine( " Quarter :  "   +  DateTimeManger.DateDiff
        (DateTimeManger.DateInterval.Quarter,date1,date2).ToString());
        System.Console.Out.WriteLine( " Seconds :  "   +  DateTimeManger.DateDiff
        (DateTimeManger.DateInterval.Second,date1,date2).ToString());
        System.Console.Out.WriteLine( " Week :  "   +  DateTimeManger.DateDiff
        (DateTimeManger.DateInterval.Week,date1,date2).ToString());
        System.Console.Out.WriteLine( " Year :  "   +  DateTimeManger.DateDiff
        (DateTimeManger.DateInterval.Year,date1,date2).ToString());

        System.Console.In.ReadLine();

    }

} // end of the class

From:

HP.Mahesh.UtilityManager.Libraries.DateTimeUtility