Dean,

I haven't used the ViewState property myself. But it sounds like the root problem is getting a reference the individual checkbox control by using the FindControl method. Here is a snippet from a page that contains a checkbox in a DataGrid to mark row(s) for deletion. It illustrates how to access the properties of the checkbox in each row of the grid:

        Dim DataGridRow As DataGridItem
        For Each DataGridRow In dgListing.Items
            If CType(DataGridRow.FindControl("chkSelect"), CheckBox).Checked() Then
                DeleteKeys.Add(CInt(CType(DataGridRow.FindControl("lblListingID"), Label).Text))
            End If
        Next

This code is called during postback when the user clicks the "Submit" button which is outside of the DataGrid. It examines each row in the DataGrid and adds the Primary Key value of the DataSource to an ArrayList when the checkbox is checked. The PK value is stored in a label in the grid, but you could alternatively use a For i = 0 To dgListing.Items.Count - 1 loop to get the PK value from the DataSource using the index (don't forget to account for paging).

Using this code, you should be able to compare the Checked property with the Boolean value in the DataSource to see if it has changed.

>Thanks Keith, I'm just getting back here to respond. The only way I see the ViewState property of a control is via the Parent property. I that case I get access issues because it is a protected property of the parent class. I've found lots written about the ViewState, but the examples of accessing it are few and tend to be about items manually aded to ViewState. I don't have a problem there. I can work with them fine. Have you retrieved values of controls from ViewState? I'd love to see some code doing it. Again retrieving the original value and the new value.
>
>Thanks again for your reply,
>
>~dab
>
>>>I am not using datasets. Am loading data into web page controls on first pass and using viewstate between posts. I have a datagrid that I've added a checkbox that is bound to a bool value - the datagrid is loaded with a datareader. The only actionable columns are the checkbox and a link column. I want to use a button on the form to update the database if the checkbox.checked property has changed (checked/unchecked).
>>>
>>>I only want to write to the database if there is a change.
>>>
>>>Is there a way in my codebehind to know if the value of the checkbox in the grid has changed? A reference to the old and new values?
>>>
>>>I am making it work with an additional hidden column that is bound to the same field as the checkbox, but there must be a cleaner way, right?
>>>
>>>Any help greatly appreciated,
>>>
>>>~dab
>>
>>Dean,
>>
>>You can check the control's ViewState property to see the value that was saved during the postback.