hi,
For your first problem,I suggest to read following links
and one more thing is every control has event like button click events or changed events.there is no such difficult in data controls .
http://www.deeptraining.com/litwin/Litwin_ASP_DataControlsTips.pdf
data controls has some events link itemcommand,editcommand,delete command..
Here itemcommand means it'll raise when u click on any button inside data control
And comming to your second problem
we don't pass entire data from one page to another page.we just pass productid of that product which you selected in first page.
In the second page we retrieve full information based on that productid from database and show in data control.
All the Best