'SubBrandDropDown' has a SelectedValue which is invalid because it does not exist in the list of items.

Hey,

Im writing a web form that contains 3 dropdownlist objects on the main form which are populated through sqlDataSource. These drop down lists when changed need to affect each others content. I have tried modifying the select statement or using a row filter, clearing the selection using .ClearSelection etc but I keep getting this error:

'SubBrandDropDown' has a SelectedValue which is invalid because it does not exist in the list of items.

TI've looked around on the web and there aren't any posts that explain why this is happening.

Any help would be much appreciated.

Thanks

M