Changing array values in a VBA dictionary

2020-02-06 01:06发布

问题:

I have a piece of code that does not seem to do what it is expected to do. VBA Arrays are mutable by all means, but it seems that when they are stored into a Dictionary as values of some keys, they are not mutable anymore. Any ideas?

Sub foo()
    Dim mydict As New Dictionary
    mydict.Add "A", Array(1, 2, 3)
    MsgBox mydict("A")(1)
    ''# The above shows 2, which is fine
    mydict("A")(1) = 34
    MsgBox mydict("A")(1)
    ''# The above also shows 2, which is not fine
End Sub

回答1:

It seems you'll need yet to set another var to update the array value.

mArray = mydict.Item(1)
mArray(1) = 34
mydict.Item(1) = mArray


回答2:

I would have written this answer as a comment to Mr. Irizarry's answer, but I'm not allowed. Anyway.... I tried writing that last line of code (below) to assign the array to the first item of the dictionary, but it didn't work. The array in that item remained as it was before.

mydict.items(1) = mArray

Based on what I read elsewhere, it seems to have to do with the instance of the dictionary you're calling upon. I changed it to the following line and it worked.

mydict(mydict.keys(1)) = mArray

I'm still not sure why that is the case, but there it is.



回答3:

I created a Procedure to solve the same issue, so I could keep it as a "oneliner":

Private Sub pReplaceDicArray(Dic As Object, kEy As Variant, Element As Integer, NewValue)
    Dim tempArray As Variant
    tempArray = Dic(kEy)
    tempArray(Element) = NewValue
    Dic(kEy) = tempArray
End Sub
' call as:
' Call mReplaceDicArray(Dic, "A", 1, 8)