MS Access 表格；仅当值为 0 时才锁定控件，而当值为空时则不锁定

Question

当子窗体的总和为0时，我需要锁定主窗体和子窗体上的所有控件。主窗体上保存该值的未绑定控件被命名为

sumBalance

，控件源拾取子窗体的总和形式

=Nz([frm_0_accs_fin_trans_journ_subf]![JournalTotal],"")

我在主窗体上的当前事件中制作了两个替代VBA代码：

If IsNull(Me!sumBalance) Then
        Me!fin_trans_id.Locked = False
        Me!fin_trans_tstamp.Locked = False
        Me!fin_trans_description.Locked = False
        Me!frm_0_accs_fin_trans_journ_subf.Locked = False
    ElseIf Me!sumBalance < 0 Then
        Me!fin_trans_id.Locked = False
        Me!fin_trans_tstamp.Locked = False
        Me!fin_trans_description.Locked = False
        Me!frm_0_accs_fin_trans_journ_subf.Locked = False
    ElseIf Me!sumBalance > 0 Then
        Me!fin_trans_id.Locked = False
        Me!fin_trans_tstamp.Locked = False
        Me!fin_trans_description.Locked = False
        Me!frm_0_accs_fin_trans_journ_subf.Locked = False
    ElseIf Me!sumBalance = 0 Then
        Me!fin_trans_id.Locked = True
        Me!fin_trans_tstamp.Locked = True
        Me!fin_trans_description.Locked = True
        Me!frm_0_accs_fin_trans_journ_subf.Locked = True
End If

If Me!sumBalance = 0 Then
        Me!fin_trans_id.Locked = True
        Me!fin_trans_tstamp.Locked = True
        Me!fin_trans_description.Locked = True
        Me!frm_0_accs_fin_trans_journ_subf.Locked = True
    Else
        Me!fin_trans_id.Locked = False
        Me!fin_trans_tstamp.Locked = False
        Me!fin_trans_description.Locked = False
        Me!frm_0_accs_fin_trans_journ_subf.Locked = False
End If

我预计这两个 VBA 代码都会导致主窗体控件和子窗体在除控件

sumBalance

= 0 之外的所有其他条件下都会解锁。

但是当子表单中没有记录而导致

sumBalance

字段为空时，表单也会被锁定，无法创建新记录。

我错过了什么？

Answer 1

无法检查不存在的记录，所以先统计一下记录：

Dim Locked As Boolean

If Me!NameOfYourSubformCONTROL.Form.RecordsetClone.RecordCount > 0 then
    Locked = (Nz(Me!sumBalance.Value, 0) = 0)
End If

Me!fin_trans_id.Locked = Locked
Me!fin_trans_tstamp.Locked = Locked
Me!fin_trans_description.Locked = Locked
Me!frm_0_accs_fin_trans_journ_subf.Locked = Locked