Vba DLookUp返回运行时错误424-需要对象

我是VBA新手，正在尝试获取我正在编写的宏，以检查是否已经存在与要添加的新记录的日期/班次组合相对应的预先存在的记录。为此，我尝试使用DLookup在数据库中进行搜索，只有当DLookup返回Null时才允许新记录，除非它找到一个日期和移位都与新数据匹配的记录（我使用的是使用这两个数据段的复合主键）。唉，正如标题所说，我一直在得到运行时错误424，当我调试它时，它会突出显示

lookTest = Access.DLookup("Shift", "trialTable", "[Date of Production]=#" & shiftDate & "#" & "And [Shift]='" & currentShift & "'")

作为问题线。（“Shift”和“Date of Production”是用作复合键的两列的列标题，“trialTable”是我正在使用的表，“shiftDate”是日期，“currentShift”是字符串），就我所知，我的语法是正确的，所以我不知道在这一点上哪里出了问题（这可能是一些愚蠢而明显的事情，我敢肯定）。如果有帮助，下面是导致这一点的其余代码，以防我之前把事情搞砸了，而计算机只是在它到达那一行之前才意识到。非常感谢任何帮助，谢谢

Sub DatabaseUpdate()
' exports data from the active spreadsheet to a table in an Access database
' this procedure must be edited before use
Dim cn As ADODB.Connection, rs As ADODB.Recordset
    ' connect to the Access database
    Set cn = New ADODB.Connection
    cn.Open "Provider=Microsoft.Ace.OLEDB.12.0; " & "Data Source=H:\TestingDatabase.accdb;"
    ' open a recordset
    Set rs = New ADODB.Recordset
    rs.Open "trialTable", cn, adOpenKeyset, adLockOptimistic, adCmdTable
    ' all records on a table
    With rs
        .AddNew 'create a new record

        'Ask the user which shift the report is for.
        Dim currentShift As String
        Dim shiftDate As Date
        Dim shiftCheck As Boolean
        shiftCheck = False

        ' Request and check if the user has entered in a valid shift. If so, continue. If not, inform them and then repeat the request for the shift identity.
        Do While shiftCheck = False
            currentShift = UCase(InputBox("Which shift is this entry for? Please input only A, B, or C. (not case-sensitive)"))
            If currentShift = "A" Or currentShift = "B" Or currentShift = "C" Then
                shiftCheck = True
            Else
                wrongLetterWarning = MsgBox("Sorry, that is not an accepted response (A, B, or C). Please try again.", vbOKOnly)
            End If
        Loop

        ' Request the date the shift occured on. MM/DD/YYYY format is important as the date and shift together form the database's primary key.
        shiftDate = InputBox("On which date did this shift occur? Please use MM/DD/YYYY format.")

        'Check to make sure that there isn't already a pre-existing record for the date/shift combination.
        Dim lookTest As Variant
        lookTest = Access.DLookup("Shift", "trialTable", "[Date of Production]=#" & shiftDate & "#" & "And [Shift]='" & currentShift & "'")

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我在Excel中测试了DLookup，它发现该表中的数据库是否处于物理打开状态。由于您已连接到数据库，并且已经打开了一个记录集，请对记录集应用筛选器

'code to collect data
...
rs.Open "SELECT * FROM trialTable WHERE [Date of Production]=#" & shiftDate & "# And [Shift]='" & currentShift & "'", cn, adOpenKeyset, adLockOptimistic
If rs.EOF And rs.BOF Then
    'code to create record
    ...
Else
    MsgBox "Record already exists."
End If

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什么是

Access

？打开

选项Explicit

，看看编译它时会发生什么。@GSerg:MS Access@braX:首先它让我将变量errowlettwarning指定为变量，现在出于某种原因它将Access标记为变量（它不是一个变量）并且说它是未定义的。当然它是未定义的。在MS Access对象模型中没有

Access

这样的东西。但是有

应用程序

，并且它确实有

DLookUp

作为它的方法。@Grahamphone是Excel项目或Access项目中包含的VBA代码吗？

数据库中的代码注释eUpdate

提到了“excel电子表格”。