Selecting a range of rows in a GridView

Question

I would like to enhance an existing GridView that allows any number of rows to be selected for follow-on processing by clicking a CheckBox in the first column of each row. Each row must now be selected individually, and I would like to allow a range of rows to be selected by doing something like clicking the first CheckBox in the range and then shift/clicking the last CheckBox in the range. It would be nice if the range could be unselected in the same manner, but that is not essential. Any suggestions are greatly appreciated. Regards, Steve B