vba - 为什么 "If Value is Nothing"抛出 "Object Required (Error 424)"

Question

以下代码抛出 Object Required (Error 424)在 if 语句比较 Nothing独立于给定的值。为什么？

Public Function SqlizeCellValue(ByVal Value As Variant) As Variant
    If Value Is Nothing Then
        SqlizeCellValue = Nothing
    ElseIf Value = Null Then
        SqlizeCellValue = Null
    ElseIf Value = "" Then
        SqlizeCellValue = Null
    ElseIf Value = "0" Then
        SqlizeCellValue = Null
    ElseIf Value = "---" Then
        SqlizeCellValue = Null
    ElseIf LCase(Value) = "n.c." Then
        SqlizeCellValue = Null
    Else
        SqlizeCellValue = Value
    End If
End Function
Public Sub TestSqlizeCellValue()
    Debug.Assert SqlizeCellValue("") Is Null
    Debug.Assert SqlizeCellValue("0") Is Null
    Debug.Assert SqlizeCellValue("---") Is Null
    Debug.Assert SqlizeCellValue(Nothing) Is Nothing
    Debug.Assert SqlizeCellValue(Null) Is Null
End Sub

Answer 1

因为 Value在您的函数定义中设置为类型 Variant只有一个 Object可以 Set至 Nothing