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OlimilO

Intermediate

Posts: 277

Location: Germany

Occupation: software engineer

1

Tuesday, March 3rd 2009, 3:56pm

storing an enum-constant in a collection

Hi

I tried this, but I encountered some problems

Jabaco Source

 
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Option Explicit
Public Enum MyEnum
    FlagNone = 0
    Flag0 = 1
    Flag1 = 2
    Flag2 = 4
    Flag3 = 8
End Enum
Dim col As Collection
Public Sub Command1_Click()
   
   Dim f As MyEnum = MyEnum.Flag2   
   MsgBox f
   
   col = New Collection
   
   Dim b As Boolean
   
   b = col.Add(f)
   MsgBox b ' why false?
   
   Dim f1 As MyEnum
   
   'f1 = col.Item(1)
   'ClassCastException: java.lang.Long cannot be cast to MyEnum
   'why?
      
   b = col.Add(1234)
   
   MsgBox b ' why false?
   
   Dim l As Integer'Long
   l = col.Item(1)
   
   'f1 = Cast(l, MyEnum) 'does not compile - why?
   
   f1 = l   
   MsgBox l & " " & f1
   
   l = col.Item(2)
   
   f1 = l
   MsgBox l & " " & f1
   
End Sub


?(

many thanks in advance

OlimilO

A1880

Intermediate

Posts: 500

Location: Hanover, Germany

Occupation: Software Engineer

2

Tuesday, March 3rd 2009, 4:27pm

Collections are used to store VBVariant Objects

Hi,
Java Collections are used to store VBVariant Objects rather than simple scalar variables.
An Enum is a non-Object. To store Enums in a Collection, you'ld have to assign the Enum value to an instance of VBVariant.
VBVariant is a "wrapper object" around various data types including a normal integer.

Happy experimenting!

A1880

This post has been edited 1 times, last edit by "A1880" (Mar 4th 2009, 12:40pm)

Manuel

Administrator

Posts: 255

Location: Erlangen, Germany

Occupation: Software Developer

3

Tuesday, March 3rd 2009, 8:25pm

Jabaco Source

 
1

MsgBox b ' why false?


Next Framework-update will fix that. FYI: I'll publish the access to the subversion repository very soon - I think that will speedup the future development of the framework.

Jabaco Source

 
1

f1 = Cast(l, MyEnum) 'does not compile - why?


Beta2 can handle that. Sorry for the procrastination. I have smaller problems with the language design. Some modifications are more extensive than I thought.

A1880

Intermediate

Posts: 500

Location: Hanover, Germany

Occupation: Software Engineer

4

Tuesday, March 3rd 2009, 11:19pm

Hi,
another try to store enums in collections.
I have used VBVariant as wrapper objects.
Currently, casting of enums does not really work.

Source code

 
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Option Explicit
Public Enum MyEnum
    FlagNone = 0
    Flag0 = 1
    Flag1 = 2
    Flag2 = 4
    Flag3 = 8
End Enum

Dim col As Collection

Public Sub Command1_Click()   
   Dim b As Boolean
   Dim f As MyEnum = MyEnum.Flag2   
   Dim f1 As MyEnum
   Dim l As Integer
   Dim o As Object 
   Dim v As VBVariant

   MsgBox "1:: MyEnum.Flag2: " & f
   
   col = New Collection
      
   v = e2v(f)
   b = col.Add(v)
   MsgBox "2:: col.Add: " & b ' why false?
      
   v = col.Item(1)
   f1 = v2e(v)
      
   v = New VBVariant(1234)
   b = col.Add(v)
   
   MsgBox "3:: " & b ' why false?
   
   v = col.Item(2)
   l = v.intValue
   
   'f1 = Cast(l, MyEnum) 'does not compile - why?
   
   f1 = l   
   MsgBox "4:: " & l & " " & f1
   
   o = col.Item(1)
   v = Cast(o, VBVariant)
   l = v.intValue 
   
   f1 = l
   MsgBox "5:: " & l & " " & f1   
End Sub

Private Function e2v(e As MyEnum) As VBVariant
   Dim i As Integer 
   Dim v As VBVariant 
   
   '  the following does not work (yet)
   ' v2i = New VBVariant(Cast(e, integer))
   
   Select Case e
   Case FlagNone:
      i = 0
   Case Flag0:
      i = 1
   Case Flag1:
      i = 2
   Case Flag2:
      i = 4
   Case Flag3:
      i = 8
   End Select
   
   v = New VBVariant(i)
   e2v = v
End Function

Private Function v2e(v As VBVariant) As MyEnum 
   '  the following does not work (yet)
   ' v2e = Cast(v.intValue, MyEnum)
   
   Select Case v.intValue 
   Case 0:
      v2e = myenum.flagnone
   Case 1:
      v2e = myenum.flag0
   Case 2:
      v2e = myenum.flag1
   Case 4:
      v2e = myenum.flag2
   Case 8:
      v2e = myenum.flag3
   End Select      
End Function


Enjoy!

A1880

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