In Reporting Services how to filter second drop down list based on selection in first drop down list?

Question

In a Reporting Services Report, How do I filter a second drop down list of cars to only show cars whose ManufacturerId is equal the selected Manufacturer (from the first drop down list)?

Report Datasets

I have 2 datasets.

Dataset 1. A list of Manufacturers. From a stored procedure Report_Manufacturers_P

Dataset 2. A list of Cars, including a column called Manufacturers id. From a stored procedure Report_Cars_P

Report Parameters

On the Report I have 2 Parameters.

Parameter 1. ManufacturerId. Set from A drop down list of Manufacturers (DataSet 1).

Parameter 2. CarId. Set from A drop down list of Cars (DataSet 2).

I've tried..

Creating another sproc called Report_Manufacturer_Cars_P that takes the ManufacturerId as an integer and returns a list of cars made by that manufacturer.

Any Ideas. As selecting a Manufacturer doesn't seem to want to kick off anything that filters the C开发者_StackOverflow中文版ar list?

Thanks in advance,

-- Lee

I've managed to do this by using the Report_Manufacturer_Cars_P as the source for the second dataset, but setting the CarId Report parameter to be a Multi-Value property.

For some reason this second drop down list now updates itself depending on what is selected in the first drop down list.

I think part of my problem was that in the Visual Studio 2008 editor when previewing the report dropdowns do not cause a 'postback' whereas when they are published they do!