使用 Collection.Add 使用自定义对象填充 VBA 集合

Question

我正在尝试在 For 循环中通过 sampleCollection.Add 添加自定义对象（事务）。

如果我将字符串而不是对象添加到集合中，则代码有效。

Public Function PopCollection()
    Dim sampleCollection As New Collection
    Dim objTrans As New Transaction
    Dim objTrans2 As New Transaction


    '********** SETUP ARRAY FOR LOOP *************
    Dim arrA(0 To 1) As String
    arrA(0) = "Description 1"
    arrA(1) = "Description 2"


    '********** POPULATE COLLECTION *************
    For n = 0 To 1
        objTrans.DESC = arrA(n)
        Call sampleCollection.Add(objTrans)
    Next n


    '********** ITERATE THROUGH COLLECTION *************
    For n = 1 To sampleCollection.Count
        Set objTrans2 = sampleCollection.Item(n)
        Debug.Print n & " - " & objTrans2.DESC
    Next n

End Function

此代码底部的Debug.Print n & " - " & objTrans2.DESC 行输出了两次“Description 2”。我希望它输出“描述 1”和“描述 2”。

这是Transaction类中的信息：

Public PTXN As Integer
Public ACCTID As Integer
Public CHECKNUM As String
Public DESC As String
Public STATUS As String
Public TRANSACTIONDATE As String
Public SPLIT_DESC As String
Public SPLIT_AMT As Single
Public SPLIT_CATEGORY As Integer

我只在 Excel 的 VB 编辑器中添加了属性声明。我复制/粘贴了那里列出的内容。

Answer 1

无法使用 Collection.add 使用自定义对象填充 VBA 集合

代码两次输出“描述 2”

简单来说，这样做总是更好：

    Dim FooCollection As Collection
    Set FooCollection = New Collection
    
    Dim FooClass As classFoo
    Set FooClass = New classFoo
    FooCollection.Add FooClass

而不是：

    Dim FooCollection As New Collection
    etc

正如我最近发现的那样，后者会导致非常微妙且不那么明显的问题，并且可能不会产生任何错误。

Answer 2

更简单的版本是将 n=0 设置为 SampleCollection.Count，因为数组的索引以 0 开头，而您的 n 以 1 开头...

For n = 0 To sampleCollection.Count
    Set objTrans = sampleCollection.Item(n)
    Debug.Print n & " - " & objTrans.DESC
Next n

Answer 3

您需要创建一个新的 objTrans 实例。您正在做的是将 DESC 设置为 Description 1，添加到集合中，然后将 DESC 更改为 Description 2（不创建新的 objTrans 实例），然后再次将同一实例添加到集合中。以下是我的做法。

Public Function PopCollection()

    Dim sampleCollection As Collection
    Dim objTrans As Transaction
    Dim arrA As Variant
    Dim n As Long

    arrA = Array("Description 1", "Description 2")
    Set sampleCollection = New Collection

    For n = LBound(arrA) To UBound(arrA)
        Set objTrans = New Transaction
        objTrans.DESC = arrA(n)
        sampleCollection.Add objTrans
    Next n

    For n = 1 To sampleCollection.Count
        Set objTrans = sampleCollection.Item(n)
        Debug.Print n & " - " & objTrans.DESC
    Next n

End Function

Answer 4

稍加修改的表单（没有 Transaction 类）按我的预期工作。我相信有一个错误是你的 Transaction 类。可以贴一下代码吗？