SQL server management studio - insert IF expression in view

I can enter a regular calculated expression into a view (as a calculated field using other fields of the db) but when I try using an IF expression it does not work. For some strange reason the error message is about incorrect syntax next to =.

Anybody knows if it is possible using IF functionms in this case (somebody told me it's not and I have to use stored procedures. Only weird for me that I can use other functions (SUM, LEFT) and build expressions but not IF.