The arrow is not focusing yo next line din dtagrid view

[Dili1234]

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim pid As String = ComboBox1.SelectedItem
        myConnection = New SqlConnection(Module1.connectionString)
        myConnection.Open()

        newq.Text = Val(TextBox2.Text) - Val(TextBox1.Text)

        Dim majortable As SqlCommand = New SqlCommand("Update Product_Details Set Quantity ='" & newq.Text & "' WHERE P_ID='" & pid & " '", myConnection)

        majortable.ExecuteNonQuery()


        MessageBox.Show("Changes had done suceesfully. !", "", MessageBoxButtons.OK, MessageBoxIcon.Information, MessageBoxDefaultButton.Button1)

        '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''


        sqlcmd = New SqlCommand("SELECT P_Id,P_Selling_Price FROM Product_Details WHERE P_Id='" & pid & "' ", myConnection)
        ' sqlcmd = New SqlCommand("SELECT P_Id,P_Selling_Price FROM Product_Details  ", myConnection)

        Dim dr As SqlDataReader = sqlcmd.ExecuteReader

        Dim n As Integer = 0

        Dim tot As Integer
        ' For n = 0 To dr.Read()
        'n = 0

            While dr.Read()



                DGV1.Rows.Add()


                DGV1.Rows(n).Cells(0).Value = dr.GetString(dr.GetOrdinal("P_Id"))
                DGV1.Rows(n).Cells(1).Value = dr("P_Selling_Price").ToString
                DGV1.Rows(n).Cells(2).Value = TextBox1.Text
                DGV1.Rows(n).Cells(3).Value = Val(DGV1.Rows(n).Cells(2).Value) * Val(DGV1.Rows(n).Cells(1).Value)

                'Next

                'DGV1.Rows.Add()
                n = n + 1




            End While





        If dr.HasRows Then
            'ok
            MessageBox.Show("Succesfully updated  !!", "", MessageBoxButtons.OK, MessageBoxIcon.Information, MessageBoxDefaultButton.Button1)
        Else
            MessageBox.Show("Data doesn't exits  !!", "", MessageBoxButtons.OK, MessageBoxIcon.Information, MessageBoxDefaultButton.Button1)

        End If


        sqlcmd.Cancel()

        dr.Close()



        ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
        myConnection.Close()



        'Product_Details1(pid)
        'Product_Details1()
        refreshComponents()

    End Sub