审计跟踪代码未获取组合框列表更改

Question

我看过这篇文章：Saving changes to a multivalued ComboBox via AuditTrail

并试图将花边新闻放入我的代码中，但它就是不起作用！我真的不是很擅长SQL，但我需要完成这项工作。这是我的代码，它适用于文本框，但有人能告诉我，我的combobox下拉列表更改需要放在哪里和确切的位置吗？

提前感谢！！

Function LogChanges(lngID As Long, Optional strField As String = "")
    Dim dbs As DAO.Database
    Dim rst As DAO.Recordset
    Dim varOld As Variant
    Dim varNew As Variant
    Dim strFormName As String
    Dim strControlName As String


    varOld = Screen.ActiveControl.OldValue
    varNew = Screen.ActiveControl.Value
    strFormName = Screen.ActiveForm.NAME
    strControlName = Screen.ActiveControl.NAME
    Set dbs = CurrentDb()
    Set rst = dbs.TableDefs("ztblDataChanges").OpenRecordset

    With rst
        .AddNew
        !FormName = strFormName
        !ControlName = strControlName
        If strField = "" Then
            !FieldName = strControlName
        Else
            !FieldName = strField
        End If
        !RecordID = lngID
        !UserName = Environ("username")
        If Not IsNull(varOld) Then
            !OldValue = CStr(varOld)
        End If
        !NewValue = CStr(varNew)
        .Update
    End With
    'clean up
    rst.Close
    Set rst = Nothing
    dbs.Close
    Set dbs = Nothing
End Function

Answer 1

不能使用.Value和.OldValue获取多值字段的值。这些属性始终返回Null。据我所知，没有可靠的方法来获取旧值(而且，正确的审计跟踪不需要旧值，因为如果所有内容都经过适当审计，旧值就是之前添加的新值)。

如果仅保存新值，并且要将其保存到文本字段而不是多值字段中，则可以使用以下方法：

使用此函数可获取所有选定项的字符串值：

Public Function JoinMVF(MVFControl As Control, Optional Delimiter As String) As String
    Dim i As Variant
    For Each i In MVFControl.ItemsSelected
        JoinMVF = JoinMVF & MVFControl.ItemData(i) & Delimiter
    Next i
End Function

然后，将您的记录集片段调整为以下内容：

With rst
    .AddNew
    !FormName = strFormName
    !ControlName = strControlName
    If strField = "" Then
        !FieldName = strControlName
    Else
        !FieldName = strField
    End If
    !RecordID = lngID
    !UserName = Environ("username")
    If Not IsNull(varOld) Then 'varOld will always be Null for a multi-valued field
        !OldValue = CStr(varOld) 'Thus this will never get called
    End If
    'Add some If multivalued field then
    !NewValue = JoinMVF(Screen.ActiveControl, "; ")
    .Update
End With