Using TOPN to create a table that did not work with time slicer

[stella1215]

Hello everyone! I have a question regarding data lineage. When I created a table using TOPN function, it didn't work with my time slicer.

I'm trying to calculate the percentage change of stock price over the last 30 days. I have a slicer to let ppl choose which period they want to see. And the last 30 days will be from the last day they choose and 30 days above. And I used the last day price / the last 30 day price -1 to get the percentage change. Since I have multiple stocks with different stock codes, I want to display the top 3 stocks who have the most increase in their price.

Here's my measure I used in the TOPN function: 

Last30Days%change =
VAR _lastDate =
    CALCULATE ( MAX ( 'Calendar'[Date] ), ALLSELECTED ( 'Calendar'[Date] ) )
VAR _last30days =
    DATESINPERIOD ( 'Calendar'[Date], _lastDate, -30, DAY )
VAR _last =
    LASTNONBLANK (
        TREATAS ( _last30days, hs300data[Date] ),
        SUM ( hs300data[Close] )
    )
VAR _first =
    FIRSTNONBLANK (
        TREATAS ( _last30days, hs300data[Date] ),
        SUM ( hs300data[Close] )
    )
VAR _lastValue =
    CALCULATE (
        SUM ( hs300data[Close] ),
        FILTER ( hs300data, hs300data[Date] = _last )
    )
VAR _firstValue =
    CALCULATE (
        SUM ( hs300data[Close] ),
        FILTER ( hs300data, hs300data[Date] = _first )
    )
VAR _result =
    DIVIDE ( _lastValue, _firstValue ) - 1
RETURN
    _result

Here's my table using TOPN to show the top 3:

Last30Days = 
TOPN (
    3,
    ADDCOLUMNS ( 
        VALUES ( 'hs300data'[Stock_Code] ), 
        "%30change", [Last30Days%change] ),
    [%30change]
)

For more details, I created a sample pbix and attached the dataset
Please pls pls, any help will be much appreciated!! I'm stuck here for two days now...

[wdx223_Daniel · Accepted solution]

calculated table can not get the filter contexts come from viusals

[stella1215]

ooo good to know! tyty. But do you happen to know what's the best way to create a measure using TOPN? My dax returns multiple columns (stock_code and the percentage change) to return the top n values, which is why I created a table for it. 

[wdx223_Daniel]

visual filter can do this work.