Parameter custom properties
Parameter custom properties in the Bold Reports® UWP Report Viewer customize how report parameters appear and behave when you preview a report.
How do I show only distinct values in a parameter?
To show only distinct values in a parameter in the Report Viewer, set the UniqueValueParameters custom property. A parameter created with data set query values may contain duplicate values. The property shows only unique values in the parameter drop-down while viewing the report, without creating a new data set. The following image shows the property setting option.
You can also provide the parameter names with comma (,) separator to set for multiple parameters.

Preview the report to see the unique values in the parameter drop-down.
