VBA映射实现
我需要在VBA中实现良好的地图类。 这是我的整数键的实现
箱子类：
Private key As Long 'Key, only positive digit Private value As String 'Value, only 'Value getter Public Function GetValue() As String GetValue = value End Function 'Value setter Public Function setValue(pValue As String) value = pValue End Function 'Ket setter Public Function setKey(pKey As Long) Key = pKey End Function 'Key getter Public Function GetKey() As Long GetKey = Key End Function Private Sub Class_Initialize() End Sub Private Sub Class_Terminate() End Sub 地图类：
Private boxCollection As Collection 'Init Private Sub Class_Initialize() Set boxCollection = New Collection End Sub 'Destroy Private Sub Class_Terminate() Set boxCollection = Nothing End Sub 'Add element(Box) to collection Public Function Add(Key As Long, value As String) If (Key > 0) And (containsKey(Key) Is Nothing) Then Dim aBox As New Box With aBox .setKey (Key) .setValue (value) End With boxCollection.Add aBox Else MsgBox ("В словаре уже содержится элемент с ключем " + CStr(Key)) End If End Function 'Get key by value or -1 Public Function GetKey(value As String) As Long Dim gkBox As Box Set gkBox = containsValue(value) If gkBox Is Nothing Then GetKey = -1 Else GetKey = gkBox.GetKey End If End Function 'Get value by key or message Public Function GetValue(Key As Long) As String Dim gvBox As Box Set gvBox = containsKey(Key) If gvBox Is Nothing Then MsgBox ("Key " + CStr(Key) + " dont exist") Else GetValue = gvBox.GetValue End If End Function 'Remove element from collection Public Function Remove(Key As Long) Dim index As Long index = getIndex(Key) If index > 0 Then boxCollection.Remove (index) End If End Function 'Get count of element in collection Public Function GetCount() As Long GetCount = boxCollection.Count End Function 'Get object by key Private Function containsKey(Key As Long) As Box If boxCollection.Count > 0 Then Dim i As Long For i = 1 To boxCollection.Count Dim fBox As Box Set fBox = boxCollection.Item(i) If fBox.GetKey = Key Then Set containsKey = fBox Next i End If End Function 'Get object by value Private Function containsValue(value As String) As Box If boxCollection.Count > 0 Then Dim i As Long For i = 1 To boxCollection.Count Dim fBox As Box Set fBox = boxCollection.Item(i) If fBox.GetValue = value Then Set containsValue = fBox Next i End If End Function 'Get element index by key Private Function getIndex(Key As Long) As Long getIndex = -1 If boxCollection.Count > 0 Then For i = 1 To boxCollection.Count Dim fBox As Box Set fBox = boxCollection.Item(i) If fBox.GetKey = Key Then getIndex = i Next i End If End Function
所有好的，如果我插入1000对键值。 但是，如果50000，程序冻结。
我怎么能解决这个问题？ 或者，也许有更好的解决scheme？
你的实现的主要问题是containsKey的操作是相当昂贵的（ O（n）复杂 ），并且在每个插入时调用它，即使它“知道”结果是什么也不会中断。
这可能会有所帮助：
... If fBox.GetKey = Key Then Set containsKey = fBox Exit Function End If ...
为了减lesscontainsKey复杂性，通常要做的事情是
- 保持键的sorting，以便您可以使用二进制search，而不是线性search
- 把钥匙保存在树上或放在一个哈希桶中
要做的最简单的事情就是使用Collection内置的（希望优化的）function按键存储/检索项目。
商店：
... boxCollection.Add Item := aBox, Key := CStr(Key) ...
检索（没有testing，根据这个答案 ）：
Private Function containsKey(Key As Long) As Box On Error GoTo err Set containsKey = boxCollection.Item(CStr(Key)) Exit Function err: Set containsKey = Nothing End Function
也可以看看：
- MSDN：如何：添加，删除和检索集合的项目（Visual Basic）
- 堆栈溢出：VBA是否有字典结构？
- Newton Excel Bach：数组vs数据集vs字典对象（和字典帮助）