TOPN calculations not working when multiple categories selected but fine for single category

[AlexanderPrime]

Hi all.

Have a table with data somewhat like this. Shortened for quick reading. Table just called Table1

Week	Year	Category	Sales Value
1	2020	Type A	100
1	2020	Type B	200
1	2020	Type C	300
2	2020	Type A	100
2	2020	Type B	200
2	2020	Type C	400
3	2020	Type A	85
3	2020	Type B	200
3	2020	Type C	300
1	2021	Type A	100
1	2021	Type B	200
1	2021	Type C	300

I have a duo of measures to go on to different Card Visuals to show the "best" and "worst" performing sales week with the below code (Will just do Best Week as I know we can swap DESC at the end with ASC to get the worst. 

Sales Value Best Week =

CALCULATE( SELECTEDVALUE(Table1[Week]), TOPN(1,Table1,Table1[Sales Value], DESC) )

There are a combo of filters on the page, one for YEAR and another for CATEGORY, Year is a hard "One item only" so it'll always be either 2020 or 2021. 
Another is for Category, multi select enabled.

The measure works fine if a single Category is selected so for the filter combo of "2020" and "Type C" it'll correctly show the result as 2.

However things get a bit messy when more than one category is selected and it starts giving random results. I can't seem to find a way for it to consider multiple categories, in this, am I missing something obvious again?

[amitchandak · Accepted solution]

@AlexanderPrime , You topN for each category this should work, measure

CALCULATE( max(Table1[Week]), TOPN(1,allselected(Table1[Week]),sum(Table1[Sales Value]), DESC) )

or

CALCULATE( max(Table1[Week]), TOPN(1,allselected(Table1[Week]),sum(Table1[Sales Value]), DESC) , values(Table1[Week]))

or use TOPN from visual level filter

or create a Rank like this and filter at the visual level

refer sub-category rank

For Rank Refer these links
https://radacad.com/how-to-use-rankx-in-dax-part-2-of-3-calculated-measures
https://radacad.com/how-to-use-rankx-in-dax-part-1-of-3-calculated-columns

[AlexanderPrime]

Thank you!

Seems I was having a case of the Wednesdays and didn't think to use the TOPN visual filter, for some reason I was convinced it was only at Measure level, the TOPN Visual filter method worked like a charm.