I have a situation where I have a gridview bound to a SqlDataSource. The SqlDataSource runs a query to use to populate the grid with data. So far, so good. However, I have a column in the gridview that I want to populate with data not included in the original query. To do so, I need to extract a key value from one of the cells in the gridview and use it to run another query and get the data that I need.

The problem is - I'm not able to access the data in the cells of the row during the RowDataBound event - at least not so far. Below is the code I've tried so far, along with the results:
'tried this
        'ID = CType(e.Row.DataItem, DataRow).Item("item_id").ToString()
        'that didn't work - DataItem was nothing

        'tried this...
        'ID = e.Row.Cells(1).Text
        'that didn't work - just gave me one of three things, depending upon the row it was on.:
        '       the column header - item_id
        '       an empty string
Any ideas? Am I doing this in the wrong place or just not calling the right function?