ms访问中的excel应用程序covariance_p无法识别范围对象

Question

我在ms访问中有以下公共功能：

'source: https://support.microsoft.com/en-us/kb/246335
Public Function COV(rs1 As DAO.Recordset, rs2 As DAO.Recordset, Returns As String) As Double

    Dim xlapp As Object, xlWb As Object, xlWs As Object, ar1 As Object, ar2 As Object

    ' Create an instance of Excel and add a workbook
    Set xlapp = CreateObject("Excel.Application")
    Set xlWb = xlapp.Workbooks.Add
    Set xlWs = xlWb.Worksheets("Sheet1")

     'Undisplay Excel and give user control of Excel's lifetime
    xlapp.Visible = True
    xlapp.UserControl = True

    ' ' Copy the recordset to the worksheet, starting in cells A1 and A2
    xlWs.Range("A1").CopyFromRecordset rs1
    xlWs.Range("F1").CopyFromRecordset rs2
    Set ar1 = xlWs.Range("D:D")
    Set ar2 = xlWs.Range("I:I")
    'Set ar1 = xlWs.Range("D1:D" & CStr(rs1.RecordCount))
    'Set ar2 = xlWs.Range("I1:I" & CStr(rs2.RecordCount))
    COV = xl.WorksheetFunction.COVARIANCE_P(ar1, ar2)
    Set ar1 = Nothing
    Set ar2 = Nothing
    Set xlWs = Nothing
    Set xlWb = Nothing
    Set xlapp = Nothing
End Function

我有一个运行时错误'424'：协方差应用程序行所需的对象：

COV = xl.WorksheetFunction.COVARIANCE_P(ar1, ar2)

协方差函数无法识别对象ar1和ar2。我把对象xlapp看得见，我在Excel中得到了这个表： 因此，当我在工作表中直接运行协方差函数时，它可以工作，但在ms访问vba，没有。