To answer question:-
I have E#Root.WFCalculationEntities in cubeview member filter. I want to add condition, if E#Root.WFCalculationEntities is blank, then E#Top.
I am during this using XFBR, but wanted to check, if someone tried if else in CV memberfilter.
Yeah, XFBR is the only way I know to do that. I would encourage you to maybe write a more generic XFBR where you pass in the prefix (E# in this case) and filter (Root.WFCalculationEntities), and if the list returned is empty, then return the passed prefix (E#) and Top. This assume of course that all of your dimensions have a Top, which is most common. That way you can reuse this logic elsewhere in your application at no additional development cost. Anyway, you’re on the right track, good luck!
