Dynamic Order For TopN Function in DAX

[Anonymous]

I am new to DAX and probably making a noob mistake. I want to change my TopN order to asc or desc order based on whether the selected measure is summing to positive or negative. But so far, I have not been successful with the below code. I am not sure why the DAX is not accepting OrderTopN variable in order definition. I have been able to solve it the long way but I wanted to know why the below code ain't working?

VAR OrderTOPN =IF([ADPR.EM]>=0,1,0)

TopN.ADPR =
CALCULATE (
[ADPR.EM],
TOPN (
'mn-value'[n-value Value],
ALL ( 'mprofile'[Org_Name] ),
[ADPR.EM],OrderTOPN
),
VALUES ( 'mprofile'[Org_Name] )
)

RETURN TopN.ADPR