Measure to Display Column Names Used as Filters

I have a simple model with 3 tables, Sales, Product, Calendar.  

Sales has Cols: ProductID, Amount, TransDate & Measure = [Total Sales]

Product has Cols: ProductID, Name

Calendar has Cols: Date, Year/Mo, Year/Qtr, MonthName (etc...)

I want to build a measure that returns the column names selected in a table visual as chosen by the user.

For example, if a user of this dataset builds a 3 column table by dragging out: 

Calendar[Year/Mo] | Product[Name] | [Total Sales] 

I'd like a measure called [You've Chosen:].  That measure, if dragged out as the 4th column in the table, would return the following text for each row in the resulting table.

"Calendar[Year/Mo], Product[Name]"

In other words, I'd like a dynamic measure of all the Table.ColName used to filter the table in which the measure is deployed.  I understand I could write a long measure with all the column names w/ IF (ISFILTERED(col), then (col), but I'd like to do it dynamically.

Thanks in advance.