private void dgvSubjects_DoubleClick(object sender, EventArgs e)
{
DataGridViewRow selected = dgvSubjects.SelectedRows[0];
int posicion = dgvSubjects.Rows.IndexOf(selected);
edit_indice = posicion;
Class.Temas auxS = SR[posicion];
txtprecio.Value = Convert.ToDecimal(auxS.Precio);
txtdescripcion.Text = auxS.Descripcion;
lblAux.Text = Convert.ToString(auxS.Id);
btnSubmit.Text = "Modificar"; accion = 1;
}