Dim Date1 As String = "07/15/2015"
Dim Time1 As String = "12:54:33"
Dim Date2 As String = "07/19/2015"
Dim Time2 As String = "12:50:33"
DateTime.DateFormat="MM/dd/yyyy" 'Ojo con las mayusculas y minúsculas!
'====================================================
'Cálculo de los dias como multiplos enteros de 24 horas (tiene en cuenta la hora del día)
'====================================================
Dim ticks1 As Long =DateTime.DateTimeParse(Date1,Time1)
Dim ticks2 As Long=DateTime.DateTimeParse(Date2,Time2)
Dim ellapsedTime As Long = ticks2-ticks1
Dim numDays As Int = ellapsedTime/DateTime.TicksPerDay
Dim numHours As Int =(ellapsedTime mod DateTime.TicksPerDay)/DateTime.TicksPerHour
Dim numMins As Int =(ellapsedTime mod DateTime.TicksPerHour)/DateTime.TicksPerMinute
Log ("Dias :"& numDays) '<---- Dará 3
Log ("Horas :"& numHours) ' 23
Log ("Minutos:"& numMins) ' 56
'======================================================
'Cálculo de los días restando solamente las fechas
'======================================================
Dim numDays As Int = (DateTime.DateParse(Date2)-DateTime.DateParse(Date1))/DateTime.TicksPerDay
Log ("Dias Reales :"& numDays) ' <---- 4