Après avoir ajouté des valeurs à la collection VBA, existe-t-il un moyen de conserver la liste de toutes les clés?
Par exemple
Dim coll as new Collection
Dim str1, str2, str3
str1="first string"
str2="second string"
str3="third string"
coll.add str1, "first key"
coll.add str2, "second key"
coll.add str3, "third key"
Je sais comment conserver la liste des chaînes:
first string
second string
third string
Encore une fois: existe-t-il un moyen de conserver les clés?
first key
second key
third key
Remarque: J'utilise VBA via AutoCAD 2007
Je ne pense pas que cela soit possible avec une collection Vanilla sans stocker les valeurs de clé dans un tableau indépendant.
L'alternative la plus simple consiste à ajouter une référence à Microsoft Scripting Runtime & à la place, utilisez un dictionnaire plus performant:
Dim dict As Dictionary
Set dict = New Dictionary
dict.Add "key1", "value1"
dict.Add "key2", "value2"
Dim key As Variant
For Each key In dict.Keys
Debug.Print "Key: " & key, "Value: " & dict.Item(key)
Next
Si vous avez l'intention d'utiliser le VB6 par défaut Collection
, alors le plus simple est de:
col1.add array("first key", "first string"), "first key"
col1.add array("second key", "second string"), "second key"
col1.add array("third key", "third string"), "third key"
Ensuite, vous pouvez lister toutes les valeurs:
Dim i As Variant
For Each i In col1
Debug.Print i(1)
Next
Ou toutes les clés:
Dim i As Variant
For Each i In col1
Debug.Print i(0)
Next
Vous pouvez créer une petite classe pour contenir la clé et la valeur, puis stocker les objets de cette classe dans la collection.
Classe KeyValue:
Public key As String
Public value As String
Public Sub Init(k As String, v As String)
key = k
value = v
End Sub
Puis l'utiliser:
Public Sub Test()
Dim col As Collection, kv As KeyValue
Set col = New Collection
Store col, "first key", "first string"
Store col, "second key", "second string"
Store col, "third key", "third string"
For Each kv In col
Debug.Print kv.key, kv.value
Next kv
End Sub
Private Sub Store(col As Collection, k As String, v As String)
If (Contains(col, k)) Then
Set kv = col(k)
kv.value = v
Else
Set kv = New KeyValue
kv.Init k, v
col.Add kv, k
End If
End Sub
Private Function Contains(col As Collection, key As String) As Boolean
On Error GoTo NotFound
Dim itm As Object
Set itm = col(key)
Contains = True
MyExit:
Exit Function
NotFound:
Contains = False
Resume MyExit
End Function
Ceci est bien sûr similaire à la suggestion de Dictionnaire, sauf qu’il n’ya aucune dépendance externe. La classe peut être rendue plus complexe si nécessaire si vous souhaitez stocker plus d'informations.
Une autre solution consiste à stocker les clés dans une collection séparée:
'Initialise these somewhere.
Dim Keys As Collection, Values As Collection
'Add types for K and V as necessary.
Sub Add(K, V)
Keys.Add K
Values.Add V, K
End Sub
Vous pouvez conserver un ordre de tri séparé pour les clés et les valeurs, ce qui peut parfois être utile.
Vous pouvez parcourir votre mémoire en utilisant RTLMoveMemory et récupérer les informations souhaitées directement à partir de cet emplacement:
32 bits:
Option Explicit
'Provide direct memory access:
Public Declare Sub MemCopy Lib "kernel32" Alias "RtlMoveMemory" ( _
ByVal Destination As Long, _
ByVal Source As Long, _
ByVal Length As Long)
Function CollectionKeys(oColl As Collection) As String()
'Declare Pointer- / Memory-Address-Variables
Dim CollPtr As Long
Dim KeyPtr As Long
Dim ItemPtr As Long
'Get MemoryAddress of Collection Object
CollPtr = VBA.ObjPtr(oColl)
'Peek ElementCount
Dim ElementCount As Long
ElementCount = PeekLong(CollPtr + 16)
'Verify ElementCount
If ElementCount <> oColl.Count Then
'Something's wrong!
Stop
End If
'Declare Simple Counter
Dim index As Long
'Declare Temporary Array to hold our keys
Dim Temp() As String
ReDim Temp(ElementCount)
'Get MemoryAddress of first CollectionItem
ItemPtr = PeekLong(CollPtr + 24)
'Loop through all CollectionItems in Chain
While Not ItemPtr = 0 And index < ElementCount
'increment Index
index = index + 1
'Get MemoryAddress of Element-Key
KeyPtr = PeekLong(ItemPtr + 16)
'Peek Key and add to temporary array (if present)
If KeyPtr <> 0 Then
Temp(index) = PeekBSTR(KeyPtr)
End If
'Get MemoryAddress of next Element in Chain
ItemPtr = PeekLong(ItemPtr + 24)
Wend
'Assign temporary array as Return-Value
CollectionKeys = Temp
End Function
'Peek Long from given MemoryAddress
Public Function PeekLong(Address As Long) As Long
If Address = 0 Then Stop
Call MemCopy(VBA.VarPtr(PeekLong), Address, 4&)
End Function
'Peek String from given MemoryAddress
Public Function PeekBSTR(Address As Long) As String
Dim Length As Long
If Address = 0 Then Stop
Length = PeekLong(Address - 4)
PeekBSTR = Space(Length \ 2)
Call MemCopy(VBA.StrPtr(PeekBSTR), Address, Length)
End Function
64 bits:
Option Explicit
'Provide direct memory access:
Public Declare PtrSafe Sub MemCopy Lib "kernel32" Alias "RtlMoveMemory" ( _
ByVal Destination As LongPtr, _
ByVal Source As LongPtr, _
ByVal Length As LongPtr)
Function CollectionKeys(oColl As Collection) As String()
'Declare Pointer- / Memory-Address-Variables
Dim CollPtr As LongPtr
Dim KeyPtr As LongPtr
Dim ItemPtr As LongPtr
'Get MemoryAddress of Collection Object
CollPtr = VBA.ObjPtr(oColl)
'Peek ElementCount
Dim ElementCount As Long
ElementCount = PeekLong(CollPtr + 28)
'Verify ElementCount
If ElementCount <> oColl.Count Then
'Something's wrong!
Stop
End If
'Declare Simple Counter
Dim index As Long
'Declare Temporary Array to hold our keys
Dim Temp() As String
ReDim Temp(ElementCount)
'Get MemoryAddress of first CollectionItem
ItemPtr = PeekLongLong(CollPtr + 40)
'Loop through all CollectionItems in Chain
While Not ItemPtr = 0 And index < ElementCount
'increment Index
index = index + 1
'Get MemoryAddress of Element-Key
KeyPtr = PeekLongLong(ItemPtr + 24)
'Peek Key and add to temporary array (if present)
If KeyPtr <> 0 Then
Temp(index) = PeekBSTR(KeyPtr)
End If
'Get MemoryAddress of next Element in Chain
ItemPtr = PeekLongLong(ItemPtr + 40)
Wend
'Assign temporary array as Return-Value
CollectionKeys = Temp
End Function
'Peek Long from given Memory-Address
Public Function PeekLong(Address As LongPtr) As Long
If Address = 0 Then Stop
Call MemCopy(VBA.VarPtr(PeekLong), Address, 4^)
End Function
'Peek LongLong from given Memory Address
Public Function PeekLongLong(Address As LongPtr) As LongLong
If Address = 0 Then Stop
Call MemCopy(VBA.VarPtr(PeekLongLong), Address, 8^)
End Function
'Peek String from given MemoryAddress
Public Function PeekBSTR(Address As LongPtr) As String
Dim Length As Long
If Address = 0 Then Stop
Length = PeekLong(Address - 4)
PeekBSTR = Space(Length \ 2)
Call MemCopy(VBA.StrPtr(PeekBSTR), Address, CLngLng(Length))
End Function
Vous pouvez facilement parcourir votre collection. L'exemple ci-dessous concerne la collection spéciale Access TempVars, mais fonctionne avec n'importe quelle collection standard.
Dim tv As Long
For tv = 0 To TempVars.Count - 1
Debug.Print TempVars(tv).Name, TempVars(tv).Value
Next tv