linq to DataTable group by用法(VB.Net语法)

Module Module1

    Sub Main()

        Dim table As New DataTable
        table.Columns.Add("A", GetType(Integer))
        table.Columns.Add("B", GetType(Integer))
        table.Columns.Add("C", GetType(Integer))
        table.Columns.Add("S", GetType(Integer))
        table.Columns.Add("S1", GetType(Integer))
        table.Columns.Add("S2", GetType(Integer))
        table.Rows.Add(1, 1, 1, 1, 1, 1)
        table.Rows.Add(1, 1, 1, 2, 1, 1)
        table.Rows.Add(1, 1, 2, 3, 2, DBNull.Value)
        table.Rows.Add(1, 1, 2, 4, 2, 1)
        table.Rows.Add(1, 1, 3, 5, DBNull.Value, 1)
        table.Rows.Add(2, 1, 3, 6, 3, 1)
        table.Rows.Add(2, 1, 3, 7, 3, 1)
        table.Rows.Add(2, 1, 4, 8, 4, 1)
        table.Rows.Add(2, 1, 4, 9, 4, 1)
        table.Rows.Add(2, DBNull.Value, 4, DBNull.Value)
        table.Rows.Add(2, DBNull.Value, 4, 11)

        Dim temp = From p In table.AsEnumerable
                                    Group p By Key = New With {Key .A = p("A"), Key .B = p("B"), Key .C = p("C")} Into g = Group
                                    Select New With {
                                        .key = Key, _
                                        .Suryo1 = g.Sum(Function(x) If(IsDBNull(x("S")), 0, x("S")))
                                    }

        Dim a = temp.ToList()
        Dim s = ""
    End Sub

End Module
Module Module1

    Sub Main()

        Dim tab