datagridview column

i m working on windows application project for a library. I have a datagridview with a column "Date" with the dates that the books were borrowed. i want to have a second column with the number of days that a member is holding a book. So i want a function that take the date from date column and the current date and make a subsrtraction of dates to find it. any help please?

Have a look at the Expression property of the DataColumn here: http://msdn.microsoft.com/en-us/libr...xpression.aspx

Good luck.