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Case select drops through valid cases to case else
Resolved · Medium Priority · Version 2003
Reply Fri 9 May 2008, 09:38Delegate Peter said...
Peter has attended:
Access Advanced course
Access VBA course
Case select drops through valid cases to case else
What is wrong with this code ?
When I run it it drops through to Case Else
Public Sub TestCase()
Dim r As Integer
r = 1
Debug.Print "opening values ", r, vbOK, vbCancel
Select Case r
Case r = 1
Debug.Print " R = 1"
Case r = vbOK
Debug.Print " R = vbOK"
Case r = vbCancel
Debug.Print " R = vb Cancel"
Case Else
Debug.Print "else case values ", r, vbOK, vbCancel
End Select
End Sub
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RE: Case select drops through valid cases to case else
Hi Peter
Thank You for your question
The third line of your code is in fact incorrect. Instead of
debug.print "Opening Values",r, vbOK, VbCancel
Should it not be
inputbox "Opening Values",r, vbOK, VbCancel
Your code is not falling through to case else, but is rather simple excecuting the third line of code
If this doesn't help, feel free to get back to me
Regards
Stephen
Reply Tue 13 May 2008, 17:41Delegate Peter said...
RE: Case select drops through valid cases to case else
Dont see that - in particular I dont see why inputbox is necessary to set the opening values.
When I run it the results from the immediate window are:
opening values 1 1 2
else case values 1 1 2
Which suggests to me that
Line 3 is executing
and that all the variables have their expected values
and then that
it is dropping thru to the case else line
Peter
RE: Case select drops through valid cases to case else
Peter,
You've been caught out by VBA's syntactic confusion between = as assignment and = as a boolean equality expression. This is bad language design (most other languages distinguish these in some way, either := for assignment, or == for equality).
The syntax for what you want is:
Select Case r
Case 1 'NOT Case r = 1
...
The VBA syntax allows Case X, where X is any expression, not just a literal value. So if r equals 1, then it would match
Case (4 - 3)
So in your code X is the boolean expression 'r = 1', which happens to be True. Since r does not equal True, the case fails.
Now, you might wonder how a Boolean expression can type-match an Integer. The problem is that True and False are implemented as Integers. Specifically, False is zero. To show this, try this:
Public Sub TestCase2()
Dim r As Integer
r = 0
Debug.Print "opening values ", r
Select Case r
Case False
Debug.Print "0 = False"
Case Else
Debug.Print "else case values ", r
End Select
End Sub
You should get the output "0 = False".
This has to be regarded as a serious fault with the language, in my opinion.
/Roy
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