Question : How to test if a control has data

Here is my code.
=IIf([Field1]="Yes","X"," ")

This code will mark my field with an X if Field1 has Yes in it. What do I replace Yes with if the field has any data in it? Even better but not a big deal is if field1 has any data other than a space.

Answer : How to test if a control has data

IIF(Len(Trim([Field1]) & "")>0,"X","")