Visual Basic.NET - Multiplicar el dato de una fila con todos los datos de otra fila

With DataGridView1

    For i = 0 To .RowCount - 1

        Dim xa, xb As Double

        xa = .Rows(i).Cells(0).Value

        For ii = 0 To DataGridView2.RowCount - 1

            xb = .Rows(ii).Cells(0).Value

        Next

        DataGridView3.Rows(i).Cells(0).Value = xa * xb

    Next

End With

Private Sub Button5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button5.Click

    Dim C As Integer = 2 ' Numérico de la coluna para testar. Para este prueba, elijo coluna C2

    If DataGridView3.Rows.Count > 1 Then   ' escribir 0 si no ultima linea vacia en el DataGridView3

        DataGridView3.Rows.Clear()

    Else

        For RDGV1 = 0 To DataGridView1.Rows.Count - 2 ' escribir -1 si  no ultima linea vacia en el DataGridView1

            For RDGV2 = 0 To DataGridView2.Rows.Count - 2 ' escribir -1 si  no ultima linea vacia en el DataGridView2

                Dim V_DGV3 As Double

                V_DGV3 = DataGridView1.Item(C, RDGV1).Value * DataGridView2.Item(C, RDGV2).Value

                DataGridView3.Rows.Add(V_DGV3, "", "")

            Next

        Next

    End If

End Sub