>>But it's pointless - a .NET string is *never* DBNull.Value......
>
>If you do a select, get that record into a DataRow, and one of the table field was null, initialize loRow("FirstName") to that variable would make it null, isn't it?

But DataRow Items are Objects that must be cast to the relevant .NET type - and this can only be done if they are not DBNull.Value. So e.g:

dr("SomeString") = DBNull.Value
        Dim s As String
        If dr("SomeString") Is DBNull.Value Then
            s = Nothing
        Else
            s = CStr(dr("SomeString"))
        End If

(so s cannot be DBNull.Value)
If you're dealing with an integer data item in a DataRow you can test using:

dr.IsNull("SomeInt")