public void MostrarEmpleados()
        {
            DataSet Dts = new DataSet();

            Dts = Ws.GetListaEmpleados("", "", "S");
            GridViewEmpleados.DataSource = Dts;
            GridViewEmpleados.DataBind();

            DropDownListNif.DataSource    = Cargar_Personas();
            DropDownListNif.DataTextField = "NIF";
            DropDownListNif.DataBind();
        }
        public void Cargar_Nif()
        {
            DataSet Dts = new DataSet();

            Dts = Ws.GetListaPersonas("", "", "", "", "", "", "", "", "Q");

            DropDownListNif.Items.Clear();
            DropDownListNif.DataSource = Dts;
            DropDownListNif.Items.Add(new ListItem(""));
            DropDownListNif.DataTextField  = "NIF";
            DropDownListNif.DataValueField = "NOMBRE_COMPLETO";
            DropDownListNif.DataBind();
        }