I am working on a time entry form to interface with an existing accounting package. I need help with a particular calculation.

The week ending date for a payroll is always on a Saturday, which the program treats as day #7. I have 7 text boxes (Mon - Sun) for entering the time for each day on my form and I have to calculate the date the day falls on as well as the day number.

I have a few questions to help me get started:
[list=1][*]Is there a way to make sure a date entered into a text box is always a Saturday? In VBA I could use this If Not IsSaturday(WeekEnding) Then[*]Are there built in intrinsic day numbers? For instance does VB.net treat Monday as a 1 (or whatever number it may be?)[/list=1]