[RESOLVED] Where to throw Custom Exception

[mojo69]

I am pulling a starting date out of a table in the database. The field is a text field in an Access DB. I created a function to validate the date.

        public bool IsDate(String testDate)
        {
            DateTime dtTest;
            return DateTime.TryParse(testDate, out dtTest);
        }

This works and returns to me true or false. I am trying to figure out where the best place to use this code, in the function(FindStartDate) that returns the date? Or after the function is called like the following?

                        String DateRangeStart = FindStartDate(strComp);
                        if (util.IsDate(DateRangeStart) == false)
                        {
                            ....
                        }

I think either way will work but which way is a better design?

Thanks.