Forms Data Controls :: How To Retrieve The Value For The Id Column For Each Row In A Gridview

I want to retrieve the value for the id column for each row in a gridview. I dont want this in a gridview rowdatabound function or anyhting, but an external function.

Normally I would do something like:

Convert.ToInt32(DataBinder.Eval(e.Row.DataItem, "id"))

in a rowdatabound event. I now want this from another function, something like:

Private Sub GetGridviewIds()
'THIS DOESNT WORK!
Dim ttypeId As Integer = gvTickettypes.Rows(i).DataItem("id")
End Sub

So how can I access the data value in a gridview row?