hey,
You should be able to put an inline anchor in your datagrid. The syntax for this is:
<a name="someid">...</a>
Usually, you put this anchor around the title of your item, or the contents of the first column in your datagrid.
To automatically scroll to this item, then you append #someid to the end of your querystring.
You should be able to get this effect with a little javascript glue that executes after the textbox.
Good luck!