文本更改时C＃报告数据刷新

Question

如何在TextBox文本更改时使报表刷新报表数据？

     private void LetoviIzvjestajForm_Load(object sender, EventArgs e)
      {
        this.reportViewer1.LocalReport.ReportEmbeddedResource ="eProdaja.Izvjestaji.LetoviIzvjestaj.rdlc";
      }


       private void txtNazivLeta_TextChanged(object sender, EventArgs e)
        {
            List<esp_Let_Izvjestaj_Result> ds = DALet.SelectLetByName(txtNazivLeta.Text);
            ReportDataSource rds = new ReportDataSource("DataSet1", ds);
            reportViewer1.LocalReport.DataSources.Add(rds);

            reportViewer1.RefreshReport();
        }

当我输入一个字母时，它有效。但是当我输入更多字母时，报告中的结果不会改变。

解决！

private void txtNazivLeta_TextChanged(object sender, EventArgs e)
        {

            if (ds.Count != 0)
            {
                ds.Clear();

                ds = DALet.SelectLetByName(txtNazivLeta.Text);
                ReportDataSource rds = new ReportDataSource("DataSet1", ds);
                reportViewer1.LocalReport.DataSources.Clear();
                reportViewer1.LocalReport.DataSources.Add(rds);
                reportViewer1.RefreshReport();

            }
            else
            {

                ds = DALet.SelectLetByName(txtNazivLeta.Text);
                ReportDataSource rds = new ReportDataSource("DataSet1", ds);
                reportViewer1.LocalReport.DataSources.Add(rds);
                reportViewer1.RefreshReport();

            }


        }


    }