dynamic legend based on slicer selection - possible?

Hi po ,

I have answered to a similar post a few days here is the data I used and the solution but adjusted to your needs

SALES:

PRODUCTS:

VENDOR: 

Create a table with both tables you need:

Type        Value

Now do the following measure:

Sum Sales =
VAR SelectedType =
    SELECTEDVALUE ( Slicer[Type] )
VAR Selected_Value =
    VALUES ( Slicer[Value] )
RETURN
    SWITCH (
        SelectedType ;
        "Vendor"; CALCULATE ( SUM ( Sales[QUANTITY(€)  ] ); Vendors[VENDOR_ID  ] IN Selected_Value);
        CALCULATE ( SUM ( Sales[QUANTITY(€)  ] ); Products[CATEGORY  ] IN Selected_Value)
    )

Now use the measure as your values on the charts and the column of values on the legend as you can see legend is dinamic.

Check PBIX file attach.