public void LlenaReport()
 {
     VentasReportViewer.ProcessingMode = ProcessingMode.Local;
     VentasReportViewer.Reset();
     VentasReportViewer.LocalReport.ReportPath = Server.MapPath(@"~\UI\Reportes\ListadoDeVentas.rdlc");
     VentasReportViewer.LocalReport.DataSources.Clear();
     VentasReportViewer.LocalReport.DataSources.Add(new ReportDataSource("Ventas", list));
     VentasReportViewer.LocalReport.Refresh();
 }
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!Page.IsPostBack)
            {
                DesdeTextBox.Text = DateTime.Now.ToString("yyyy-MM-dd");
                HastaTextBox.Text = DateTime.Now.ToString("yyyy-MM-dd");

                VentasReportViewer.ProcessingMode = ProcessingMode.Local;
                VentasReportViewer.Reset();
                VentasReportViewer.LocalReport.ReportPath = Server.MapPath(@"~\Reportes\ListVentas.rdlc");
                VentasReportViewer.LocalReport.DataSources.Clear();
                VentasReportViewer.LocalReport.DataSources.Add(new ReportDataSource("Ventas", Funciones.Ventas(filtrar)));
                VentasReportViewer.LocalReport.Refresh();
            }
        }