URL Filtering by dates not working

There are many ways to display the detail behind a distinctcount measure.

Take this model:

To show the distinctcount of items by category where the validity is "Yes", we have this measure:

Items where Validity is Yes =
CALCULATE (
    DISTINCTCOUNT ( 'Item Table'[dItem] ),
    FILTER ( 'Validity Table', 'Validity Table'[dValidity] = "Yes" )
)

If you want to list the items in a table visual, you can use a measure as follows:

Display Items =
VAR _Items =
    CALCULATETABLE (
        VALUES ( 'Item Table'[dItem] ),
        FILTER ( 'Item Table', [Items filter] >= 1 )
    )
RETURN
    CONCATENATEX ( _Items, 'Item Table'[dItem], ", " )

If you want the values to be displayed as a tooltip, you can create a report tooltip page, with for example a table visual for items. You will need the following measure to filter the visual to display the correct values:

Items filter =
COUNTROWS (
    CALCULATETABLE (
        VALUES ( 'Item Table'[dItem] ),
        FILTER ( 'Validity Table', 'Validity Table'[dValidity] = "Yes" )
    )
)

If you actually want to be able to drillthrough to a new page where there is a visual listing the values, you can set it up as follows:

Setting up the page will cretae a "Back" button by default to take the user back to the original pageYou navigate to the drillthrough page by right-clickin on a rowYou can set up a more direct drillthrough be setting it up in the Data/drill tab (but you will loose the default tooltips)

You can also combine these techniques if you wish: for example Report Page Tooltip & Drillthrough:

Sample PBIX file attached