iif condition

Hi,I have the following requirement and have to create the condition in SSRS based on this:'Default from from_loc_3. If from_loc3 is null use from_loc2. If from_loc2 is null use from_loc1'based on this I have created this condition but it doesnt work:=iif(Fields!FROM_LOC2.Value = "", Fields!FROM_LOC1.Value, iif(Fields!FROM_LOC3.Value = "", Fields!FROM_LOC2.Value, Fields!FROM_LOC3.Value))I mean if the value for FROM_LOC3 exists, then the value is left as blank which is wrong because if the value for FROM_LOC3 exists, then the same whould get populated.Does someone have any suggestions for this ?Thanks.