title: Calculate total hours using DateTime columns in DataGridView
body: <p>I'm struggling a bit with a calculation I need to do en every row in a datagridview. What I want is to go through all rows in a datagridview that has two columns with datetimes. One representing a LogInTime and one representing a LogOutTime. I would like to get the total number of hours and minutes between all log in times and log out times for the rows displayed in the datagridview. Any suggestions on how to implement this?</p>