爲什麼「If Value is Nothing」拋出「Object Required（Error 424）」

以下代碼在if語句處拋出Object Required (Error 424)，與Nothing比較，與給定的值無關。爲什麼？爲什麼「If Value is Nothing」拋出「Object Required（Error 424）」

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

來源

2016-07-06 Torsten Knodt

因爲'Value'是'Variant'只有一個'Object'可以設置爲' Nothing'。 – Dave

謝謝@Dave。你能否提供這個答案作爲答案，所以我可以將其標記爲已接受/正確？ –