[Serializable] attribute gives 'Declaration expected' squiggly

[Cirene]

I'm binding a datagrid to my business object. I get an error that the type
'abcshoppingcart'...is not marked as serializable.

So, I added a [Serializable] attribute in the class. But then a blue
squiggly appears with 'declaration expected'. Any idea why?

[Serializable]
Public Class abcshoppingcart
Public customer As New abccustomer
Public product As New List(Of abcproduct)

Public Sub New()
' constructor
End Sub
......

 

[Cirene]

FYI: Do it this way....

<Serializable()> Public Class xxxxxx