Gridview在更新之前检索旧值

Question

我正在使用gridview来填充数据，我检索新值但我需要旧的值用于报告目的，有没有办法可以检索这些旧值？ 我正在使用templatefield

     protected void TcGridView_RowEditing(object sender, GridViewEditEventArgs e)
    {

        TcGridView.EditIndex = e.NewEditIndex;

        FillTravelers();
    }

            protected void TcGridView_RowUpdating(object sender, GridViewUpdateEventArgs e)
    {
        GridViewRow row = TcGridView.Rows[e.RowIndex];

        //FillTravelers();
        TcGridView.EditIndex = -1;
        TextBox txtFC = row.FindControl("FCTextBox1") as TextBox;

        Label txtID = row.FindControl("IDLabel") as Label;
        Label txtDC = row.FindControl("DCLabel") as Label;
        Label txtRate = row.FindControl("RateLabel") as Label;

        String FC = txtFC.Text;
        String ID = txtID.Text;
        String DC = txtDC.Text;
        String Rate = txtRate.Text;

        double newDC = Convert.ToDouble(FC) / Convert.ToDouble(Rate);

        Transaction trs = new Transaction(Convert.ToInt32(ID), " ", " ", Convert.ToDouble(FC), Convert.ToDouble(Rate), newDC, " ", ID);
        DatabaseHandler.EditTransaction(trs);

        FillTravelers();
    }

由于 卡尔