Question on datagrid and detail modal edit page

[jen]

Hi,

I am working on a web application and have one form1.aspx page with a
Datagrid in it. When user click the edit button in the grid, it will
popup a modal page (edit1.aspx) by using JavaScript client code
(window.showModalDialog).

Question:
1. How to execute some server side codes before window.showModalDialog
client code get called? I want to get the current row info and save it
in the Session or Cache. In this way, there is no need to reload
record info from database again in edit1.aspx.

2. Or, is there a way to capture the datagrid (web controls) Click or
mousedown event so I can run some server side codes first?

2. Because there are 2 big string field, I can not use
dialogParametes. What is the best way to transfer data to edit1.aspx?
I know with window.open, window.opener is avaiable in the popup
window. But I do need Modal window/dialog here.

Thanks
Jen