Duplicate declaration

[tiredofit]

Why is it this does not compile?


It is as if it ignores the If condition and declares b regardless, so you cannot declare it "twice".

Dim a As Long


If a = 10 Then


    Dim b As String


Else


    Dim b As Long
        
End If

Thanks

 

[shg]

A dimension statement is not executable, it's a compiler directive. That's why you can't set a breakpoint on one.

You can use conditional compilation (#If/#Else) to declare variables, but the condition expression must be evaluable at compile time.

 

[shg]

E..g.,

  [URL=https://www.mrexcel.com/forum/usertag.php?do=list&action=hash&hash=Const]#Const[/URL]  a = 10
  
  [URL=https://www.mrexcel.com/forum/usertag.php?do=list&action=hash&hash=If]#If[/URL]  a = 10 Then
    Dim b           As String
  [URL=https://www.mrexcel.com/forum/usertag.php?do=list&action=hash&hash=Else]#Else[/URL] 
    Dim b           As Long
  [URL=https://www.mrexcel.com/forum/usertag.php?do=list&action=hash&hash=End]#End[/URL]  If

  Debug.Print TypeName(b)

 

[Jaafar Tribak]

@tiredofit

Alternatively, you could take advantage of the Variant type at runtime as follows :

Sub Test()

    Dim b As Variant
    Dim a As Long
    
    a = 10
    
    If a = 10 Then
        b = CStr(b)
    Else
        b = CLng(b)
    End If
    
    MsgBox TypeName(b)
    
End Sub

 

[tiredofit]

Thanks to all for the explanation and examples.