Forms VBA和Access 2007数据验证、登录故障

请容忍我，我在VBA是一个彻头彻尾的傻瓜，我本来不打算写代码，但我最终还是这么做了，因为我不知道没有它我将如何实现我想要的。我已经在网上搜索了3天，每天10个小时，运气不好。我有一个Access数据库，我想保护它。让我先解释一下我想要实现的目标：

1） 我有一个表单中的组合框，用于查找表中的值，即项的项代码。这基本上是一个库存问题。我有一个查询，它有一个计算字段，返回每个项目的剩余库存。我有另一个查询，它将商品代码作为参数，并返回该特定商品代码的剩余库存

我想做的是检查剩余库存是否为0，如果是，则在从组合框列表中选择此项目代码时，让msgbox显示一条消息，说明该项目没有库存，因此无法发行，并重置组合框（即，好像没有进行选择）

这是我的密码；组合框的afterUpdate事件：

Private Sub Item_Code_AfterUpdate()

Dim dbMyDatabase As DAO.Database

Dim rsMyRecords As DAO.Recordset

Dim strQuery As String

strQuery = "SELECT [Store_Items].[Item Code], Store_Items.[Opening Stock], IIf((Nz([Opening Stock],0)+Nz([Quantity Purchased],0)-Nz([Quantity Issued],0)<0),0,(Nz([Opening Stock],0)+Nz([Quantity Purchased],0)-Nz([Quantity Issued],0))) AS [Remaining Stock] FROM (Purchases RIGHT JOIN Store_Items ON Purchases.[Item Code] = Store_Items.[Item Code]) LEFT JOIN Issuances ON Store_Items.[Item Code] = Issuances.[Item Code] WHERE (((Store_Items.[Item Code])=[Forms]![Issuances]![Item Code]));"

Set dbMyDatabase = CurrentDb

Set rsMyRecords = dbMyDatabase.OpenRecordset(strQuery)

Dim Msg, Style, Title, Response

Msg = "This Item is out of Stock! You Cannot Issue this item!"
Style = vbOK
Title = "Warning!"

If rsMyRecords![Item Code] <= 0 Then
Response = MsgBox(Msg, Style, Title)
If Response = vbOK Then Me![Item Code].Requery

End Sub 

---

请帮忙S

好吧，我设法解决了登录问题，但我仍然坚持使用数据验证位。当我单击组合框中列表中的项目代码时，出现运行时错误3421

当我从组合框中选择一个项目代码时，这就是我希望发生的事情。我想从该商品代码的查询中获取计算字段（此计算字段包含商品的计算剩余库存），如果为0，则我想显示消息并阻止用户输入此记录，因此我想重置组合框可以吗

如果股票处于某个水平，我只想显示一个msgbox，仅此而已，通常让用户输入记录，否则，用户只需正常输入记录

我在这一行收到运行时错误3421“数据类型转换错误”：

Set rs=db.OpenRecordset（“从[InventoryStatusSpecificItem]中选择[剩余库存]，其中[Item Code]=[Forms]！[Issuations]！[ItemCBO]”，动态集）

Private Sub LoginBUtton_Click()

'Check to see if data is entered into the UserName combo box

    If IsNull(Me.CBOLogin) Or Me.CBOLogin = "" Then
      MsgBox "You must select a user type.", vbOKOnly, "No User name"
        Me.CBOLogin.SetFocus
        Exit Sub
    End If

    'Check to see if data is entered into the password box

    If IsNull(Me.TextPass) Or Me.TextPass = "" Then
      MsgBox "No Password Entered, Enter a password.", vbOKOnly, "No Password"
        Me.TextPass.SetFocus
        Exit Sub
    End If

    'Check value of password in Users to see if this
    'matches value chosen in combo box

    If Me.TextPass.Value = DLookup("Password", "Users", _
            "[UserID]=" & Me.CBOLogin.Value) Then



    ElseIf (Me.CBOLogin.Value = "Developer") Then
    DoCmd.Close acForm, "LoginForm", acSaveNo
    DoCmd.OpenForm "FullAccessNav"


    ElseIf (Me.CBOLogin.Value = "Office") Then
    DoCmd.Close acForm, "LoginForm", acSaveNo
    DoCmd.OpenForm "LimitedAccessNav"


    ElseIf (Me.CBOLogin.Value = "Store") Then
    DoCmd.Close acForm, "loginForm", acSaveNo
    DoCmd.OpenForm "LimitedAccessNav"

    Else
            MsgBox "Password Invalid. Please Try Again", vbOKOnly, _
            "Invalid Entry!"
            Me.TextPass.SetFocus

    End If

    'If User Enters incorrect password 3 times database will shutdown

    intLogonAttempts = intLogonAttempts + 1

    If intLogonAttempts > 3 Then
      MsgBox "You do not have access to this database.Please contact admin.", _
               vbCritical, "Restricted Access!"
        Application.Quit
    End If

End Sub

Private Sub ItemCBO_AfterUpdate()

    Dim db As DAO.Database
    Dim rs As DAO.Recordset

    Set db = CurrentDb()


    Set rs = db.OpenRecordset("SELECT [Remaining Stock] FROM [InventoryStatusSpecificItem] WHERE [Item Code] = [Forms]![Issuances]![ItemCBO]", Dynaset)



    If rs.Fields([Remaining Stock]) = "0" Then
    MsgBox "This item is out of stock! Cannot Issue!", vbExclamation + vbOKOnly, "Attention!", vbExclamation
    Me!ItemCBO = Null

    ElseIf rs.Fields("Stock Status") = "Order Now!" Then
    MsgBox "This item has reached its minimum quantity level. Only " + StrRemainingStock + " remains. Quantity Measured as " + StrMeasuredIn, vbExclamation + vbOKOnly, "Attention!"

    Else
    Me!ItemCBO.Requery

    End If

    'close recordset
    rs.Close
    Set db = Nothing