Convert object type

Question

Hello good afternoon to everyone. could you please help me with the following

I would like to bring to a datagridvew the corresponding sales between two date ranges

for this I have the following code

namespace CapaLogica
{
    public class VentasEntreFechasDTO
    {
        public string NumeroVenta { get; set; }
        public string Producto { get; set; }
        public string Unidad { get; set; }
        public decimal Precio { get; set; }
        public int Cantidad { get; set; }
        public decimal ValorFila { get; set; }

        //
        public static List<VentasEntreFechasDTO> Ventas(DateTime Inicio, DateTime Fin)
        {

            using (GourmetEntities db = new GourmetEntities())
            {
                var li = db.tblMaestroVentas.Include(x => x.tblDetalleVentas).Where(x => x.FechaVenta >= Inicio && x.FechaVenta <= Fin);

                return (List<VentasEntreFechasDTO>)li;
            }
        }

    }
}

this code apparently doesn't show me any error, but when I try to load it to a datagridview it shows me an error

private void BtnBuscar_Click(object sender, EventArgs e)
{
    if(VerificarRangoFechas())
    {
        DataGridViewVentaEntreFechas.DataSource = VentasEntreFechasDTO.Ventas(DtpDesde.Value.Date, DtpHasta.Value.Date);
    }
}

 

Please how can I solve this error since I need to visualize sales between date ranges

 

please help

Roberto Melgar