vba 2427 你输入了一个没有值的表达式
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2427 You entered an expression that has no value
提问by Chin
I have a function to split up my report into separate PDF files based on a field id:
我有一个功能可以根据字段将我的报告拆分为单独的 PDF 文件id：
Public Function PrintList() As String
Dim MyPath As String
Dim MyFilename As String
Dim myId As String
Dim filter As String
MyPath = "C:\reports\"
Dim rs As DAO.Recordset
Set rs = CurrentDb.OpenRecordset("SELECT DISTINCT id FROM table")
'Loop through the set
Do While Not rs.EOF
If Not IsEmpty(rs!id) And Not IsNull(rs!id) Then
myId = rs!id
Else
myId = ""
End If
filter = "id = '" & myId & "'"
'Open report preview and auto-save it as a PDF
DoCmd.OpenReport "myReport", acViewPreview, , filter
MyFilename = "N" & myId & ".pdf"
DoCmd.OutputTo acOutputReport, "", acFormatPDF, MyPath & MyFilename, False
'Close the previewed report
DoCmd.Close acReport, "myReport"
rs.MoveNext
Loop
End Function
However, while running, I would get this error/warning:
但是，在运行时，我会收到此错误/警告：
2427 You entered an expression that has no value.
2427 您输入的表达式没有值。
This happens when the idis null. I don't even know if this is an error or a warning. After I click Ok, the function continue to runs till the end without any problem, and the output file would be named N.pdf.
当id为空时会发生这种情况。我什至不知道这是错误还是警告。单击“确定”后，该函数将继续运行到最后，没有任何问题，输出文件将命名为N.pdf.
Since this message box is not like the usual error message box, and since it doesn't give me the option to debug or end the execution, I guess it is not an error?
由于这个消息框不像通常的错误消息框，而且由于它没有给我调试或结束执行的选项，我猜这不是错误？
I have tried to suppress warning using DoCmd.SetWarnings Falsebut it doesn't work.
我试图抑制警告使用，DoCmd.SetWarnings False但它不起作用。
How can I fix this or at least suppress it so that it doesn't show up?
我该如何解决这个问题或至少抑制它以使其不出现？
回答by RBarryYoung
There's no short-circuiting in VBA, so try changing this:
VBA 中没有短路，所以尝试改变这个：
If Not IsEmpty(rs!id) And Not IsNull(rs!id) Then
myId = rs!id
Else
myId = ""
End If
to this:
对此：
If Not rs!Id Is Nothing Then
If Not IsNull(rs!id) Then
If Not IsEmpty(rs!id) Then
myId = rs!id
Else
myId = ""
End If
Else
myId = ""
End If
Else
myId = ""
End IF
