怎样在AutoCAD的VBA中判断一个EXCEL文件是否已打开

Sub test()
    If IsFileOpened("d:\accountlist.xls") Then
        MsgBox "文件已经打开！"
    End If
End Sub
Function IsFileOpened(ByVal FileName As String) As Boolean
    IsFileOpened = True
    
    ' 使用锁定方式打开文件
    On Error GoTo ErrTrap
    Open FileName For Binary Lock Read Write As #1
    IsFileOpened = False
    Close #1
    Exit Function
    
ErrTrap:
    Close #1
    On Error GoTo 0
End Function

Sub test()
    If IsFileOpened("c:\2.xls") Then
        MsgBox "文件已经打开！"
        [color=red]Workbooks("c:\2.xls").Activate[/color]
    End If
End Sub
Function IsFileOpened(ByVal FileName As String) As Boolean
    IsFileOpened = True
    
    ' 使用锁定方式打开文件
    On Error GoTo ErrTrap
    Open FileName For Binary Lock Read Write As #1
    IsFileOpened = False
    Close #1
    Exit Function
    
ErrTrap:
    Close #1
    On Error GoTo 0
End Function

Sub CAD_excel()
'先引用EXCEL
Dim ex As Excel.Application
Dim wk As Workbook
Dim wc As Worksheet
Set wk = ex.Workbooks("2.xls")   '该文件已先打开
Set wc = wk.Worksheets("sheet1")
wc.Cells(1, 1) = 2
End Sub