A workaround taken from this answer (Its not a duplicate question else I would flag it as such) is to create a hidden, multi-valued, parameter e.g. MyHiddenDataSetValues
which stores the values from “MySharedDatasetWithParameter” and then
=Parameters!MyHiddenDataSetValues.Count
gives the number of rows.
Rather clunky, so still hoping for a way to use CountRows
.
solved Get Count of Shared DataSet when defined with a Parameter