Question

Is there a difference from POV Performance / MemoryUsage initializing a object before, or after a return condition, like in the “sample”:

Function Foo() as ComplexObject

    ' is there a difference ??? '
    ' A '
    ' Dim obj as New ComplexObject() ' 

    If condition Then Return Nothing

    ' is there a difference ??? '        
    ' B '
    Dim obj as New ComplexObject()
    ...
    Return obj

End Function

Answer 1

If you mean, but comparison to:

 Dim obj as New ComplexObject()

before the If condition Then Return Nothing, then yes: there is a difference: it done before, then it will new an object each time, even if it is quickly discarded and collected from gen-0 (for the case when Nothing is returned). However, if you just declare it (without New) before the If, then the two should be identical (the position of the local variable is irrelevant, since all locals in IL are method-wide).

I don’t know the VB, but in C# you could also use a conditional operator:

return condition ? null : new ComplexObject();