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

 

[Special-K99]

I'm in noway at all a VBA expert, more a VBA novice but my guess is when VBA compiles it sees all the Dim statements in your procedures first.
Since your Dim b occurs more than once (the "If statement" is irrelevant) you receive a Duplicate Declaration error.

Cant you just Dim a different variable for the "Long" statement?

This assumption looks plausible as the same error occurs if you simply code

Dim a as String
Dim a as Long

Looks like variables can only be declared once in a subroutine.

This page says its impossible to dim a variable more than once

https://stackoverflow.com/questions/25045953/is-it-harmful-to-dim-a-variable-more-than-once

 

[tiredofit]

Thanks, I'm just curious.

VBA seems to have a lot of inconsistencies.

 

[RoryA]

What is that inconsistent with?

Perhaps you should read the language spec.

 

[tiredofit]

Not sure what the language spec says but looking at an If statement, I thought it indicates a condition and if it is met then something, else something else.

Other inconsistencies in VBA include:

not being able to add named arguments in some functions such as Instr


pressing the dot operator doesn't give you the full range of options, eg Appliction.VLookup exists but isn't presented to you

etc.

 

[RoryA]

Yes that is what an If condition means but it doesn't override the fact that you can only declare a variable once.

Regarding Instr, it is very much an anomaly (StrComp is the only other function I can think of offhand that has similar issues).

Your last comment about Application is not a VBA issue per se; it's an issue with Excel's object model.

 

[tiredofit]

Yes that is what an If condition means but it doesn't override the fact that you can only declare a variable once.

Regarding Instr, it is very much an anomaly (StrComp is the only other function I can think of offhand that has similar issues).

Your last comment about Application is not a VBA issue per se; it's an issue with Excel's object model.

Found a few more "exceptions" today:


Data Validation 250 character limit.


Transposing arrays limit of 65536.

 

[RoryA]

Again, those are to do with the Object Model, not VBA, but I’m not really sure what they are exceptions to?

 

[tiredofit]

Again, those are to do with the Object Model, not VBA, but I’m not really sure what they are exceptions to?

I guess I don't understand what you mean by Object model, as opposed to VBA.

 

[RoryA]

VBA is a generic language based on VB6. In order to be hosted by Excel or Word or any other application, it needs a reference to the object library for that application, which is what gives it access to the objects for that application - e.g. Workbooks for Excel or Documents for Word - and their relevant properties or methods.