Set/Get checkbox value in Gridview

Hi all,

Hopefully a quick one, I have a normal Gridview with normal text columns but with one holding a checkbox for an "attended" field.  

What I'm after is that when this checkbox is ticked, on CheckedChanged event I want to update the database to say the course has been attended if the Checkbox is checked.

I can access the CheckedChanged event fine from within the Gridview, but I would like the checkbox to hold the ID of the course, so I can then automatically use a "Update tbl where ID = CHECKBOXVALUE".

I can only set the bound ID to either the Text or Checked parts of the Checkbox though, so the value is appearing alongside the Checkbox in the Gridview, which I don't want to be visable, is there a way to attach the value so I can use it but no have it display next to the checkbox?

Cheers