从Listview或者Treeview的键(key)中返回一个索引值(index)

一个函数，功能如题．
Public Function ReturnIndex(List As ListView, Key As String, ReturnInt As Integer) As Boolean
    Dim TempInt As Integer
    Dim Found As Boolean
    TempInt = 1
    Found = False

    Do While (TempInt <= List.ListItems.Count) And (Found = False)

        If (List.ListItems.Item(TempInt).Key = Key) Then
            Found = True
            Exit Do
        End If
        TempInt = TempInt + 1

        DoEvents
        Loop

        If Found = False Then
            ReturnIndex = False
        Else
            ReturnIndex = True
            ReturnInt = TempInt
        End If
    End Function

'示例:
Private Sub Command3_Click()
    Dim Tempy As Integer

    If ReturnIndex(ListView1, "KEY1", Tempy) = True Then
        MsgBox "键的索引是: " & Tempy
    Else
        MsgBox "没有找到键!"
    End If
End Sub