Vista - Fully editable unbound grid

Hello,

In a Default.aspx page, I need to display an unbound grid with the
following editable columns:
Name, Location, Phone, Paid, Amount

Initially the grid would be empty with only the column headings
visible.

Based on certain conditions, the Default.aspx.cs code would fetch data
from a database.
I then need to display the data in the grid with the all fields
rendered editable.
Name would be a textbox,
Location would be a dropdown list
Phone would be a textbox
Paid would be a checkbox
Amount would be a textbox

Fetching the data is no problem for me. But I can't figure out how to
make the fields editable all at once. I don't want an 'Edit' button
for each row. Update should only happen after the user clicks on a
common Update button behind which I'll have the database update code.

Also, the textbox for Amount should only be enabled when user ticks
the Paid checkbox

My actual data and code behind queries will be much more complex so I
really need to use an unbound grid.

Any help is much appreciated.

Many Thanks,
Mirin