clears the text of textbox

protected void Submit_Click(object sender, EventArgs e)
    {
        BillOfQuantitiesObj = new BillOfQuantitiesBAO();
        foreach (RepeaterItem rr in Repeater1.Items)
        {
            BillOfQuantitiesObj.ContRegNo = ContRegNo;
            BillOfQuantitiesObj.TenderNo = TenderNo;
            BillOfQuantitiesObj.TenderSNo = TenderSNo;
            BillOfQuantitiesObj.Items = ((Label)rr.FindControl("LbItem")).Text;
            BillOfQuantitiesObj.Description = ((Label)rr.FindControl("LbDescription")).Text;
            BillOfQuantitiesObj.Unit = ((Label)rr.FindControl("LbUnit")).Text;
            BillOfQuantitiesObj.Quantity = decimal.Parse(((TextBox)rr.FindControl("LbQuantity")).Text);
           BillOfQuantitiesObj.RateInNumbers = decimal.Parse(((TextBox)rr.FindControl("RateInNumbersTB")).Text);
            BillOfQuantitiesObj.RateInfigures = ((TextBox)rr.FindControl("RateInFiguresTB")).Text;
           BillOfQuantitiesObj.TotalAmount =decimal.Parse(((TextBox)rr.FindControl("TotalAmountTB")).Text);
        ContractorBillOfQuantitiesDAO.InsertBillOfQuantities(BillOfQuantitiesObj);
            }
    }