Need help with Dynamic Fields selection based on the no of values selected in the Slicer.

Hi wickkey 

I've attached an example of how this can be done. It's an interesting application of field parameters.

Field parameters are a preview feature so need to be enabled in the "Preview features" settings.

1. Create a Field Parameter for State and City columns. I called this State/City.
2. Place this Field Parameter on the axis of the visual.
3. Create a measure called State/City Filter.
   The purpose of this measure is to filter State/City by returning 1 for the combinations we want to display (if a single state is selected and State/City = "City", or multiple states selected and State/City = "State") or 0 otherwise.
4. Add the State/City column as a visual-level filter to the visual, and select Filter type = Top N. Show Top 1 items with By value set to the State/City Filter measure. Click Apply filter.
5. Now, when a single state is selected on the slicer, the visual axis will show City, and when multiple states are selected, the visual axis will show State.

Does this work in your report?

State/City Filter = 
-- SingleState = 1 if a single state has been selected on slicer, otherwise 0
VAR SingleState =
    INT (
        CALCULATE ( HASONEVALUE ( Orders[State] ), ALLSELECTED () )
    )
-- CityOption = 1 if the current Field Parameter option = City, otherwise 0
VAR CityOption =
    INT ( MIN ( 'State/City'[State/City] ) = "City" ) 
RETURN
    -- Return 1 if SingleState & CityOption both = 1 (display city), or if SingleState & CityOption both = 0 (display state)
    INT ( SingleState = CityOption )