Question

Assuming totallvl is an integer and chclass1 has been created but chclass2 has not, why can I do this:

totallvl = chclass1.level
If chclass2 IsNot Nothing Then
    totallvl = totallvl + chclass2.level
End If

but not this?

totallvl = chclass1.level + IIf(chclass2 Is Nothing, 0, chclass2.level) 

It’s like the compiler is assuming I’ll use chclass2 in this example but not in the first example.

Answer 1

IIf is just a function; chclass2.level is evaluated regardless of what the first argument is. If you want an inline conditional operator similar to other languages, use an actual inline If (available in VB 2008 and later):

If(chclass2 Is Nothing, 0, chclass2.level)