How to make a parameter dropdown depend on the selection of another parameter drop down

“Expressions have the solution of every problem”

Let’s say you have param1 which is data bound (drop down list from dataset1), and param2 which is data bound (drop down list from dataset2).

1. Add dataset1
2. Add param1 and set its values to be “From dataset” with dataset set to dataset1
3. Add dataset2 with a parameter dataset2_param (it could be based on a data method with a parameter param, or a query with range param), dataset2_param is the parameter you want to use to filter the drop down list of the second parameter, report parameter param will be created automatically
4. Set param default value to be expression “=Parameters!param1.Value”
5. Add param2 and set its values to be “From dataset” with dataset set to dataset2
6. Add a data region
7. Preview