How to create such measure for a card

[Pbiuserr]

Hello, 
My goal is to get a count of maximum available values in slicer (I've made a filter measure of COUNTROWS(RELATEDTABLE(FACT) and put it as a filter greater or equal to 1 for the slicer, so it captures only date available in fact table) and compare it with the current values choosen in the slicers. Then, depending on how many I'll make a switch statement with certain behaviours like

-Not selected anything - "Please select period"

-Everything selected - "All period selected (" & MaxSelectionCount & ")"

-Up to 5 selections - I have concat with MonthYear values 

-Above 5 selections - Above 5 periods selected (" & Count & ")"

So far I've tried only with Not selected and Everything Selected, If I got those right then I'll be set and rest is easy

VAR _Selection =
ISFILTERED ( ' date'[MonthYear] )
VAR _Count =
COUNTROWS ( VALUES ( ' date'[MonthYear] ) )
VAR _MaxSelectionCount =
CALCULATE (
COUNTROWS ( ' date' ),
REMOVEFILTERS ( ' date'[MonthYear] ),
RELATEDTABLE ( ' FACT' )
)
VAR _Result =
SWITCH (
TRUE (),
Selection = FALSE (), "Please select period to review",
Count = MaxSelectionCount,
"All period selected (" & MaxSelectionCount & ")"
)
RETURN
Result

It is because it gives me 9, instead of 7 available values in slicer

[YukiK]

Try removing "REMOVEFILTERS ( ' date'[MonthYear] ),". It's better if you could share your file/data