wwWebListControl::DataBind
DataBind on a list control performs ControlSource binding only that sets the SelectedValue. List based binding occurs at Render() time.
o.DataBind()
Remarks
Calling DataBind() will force a ControlSource binding to occur, so the SelectedValue property will be reset to the controlsource. Generally this is not desirable on a Postback operation. Avoid calling .DataBind() on list controls manually - let it happen through Page or container based binding.