difference between 2 dates in C#

hi, i want  out put as '1'  when both from date and to date are fall in same date.

ex: if  fromdate is 21/10/2008 and todate is  21/10/2008.  i want the difference between fromdate and todate as '1'.  for salary calcutaon i want this.if  user selects both dates as same,then  he will be liable for 1 day salary.

how to do this, let mwe know

'thank you.