private void btnAgregarVariante_Click(object sender, EventArgs e)
 {
     using (EditarVarianteFrm agregar = new EditarVarianteFrm(tipo))
     {
         agregar.ShowDialog(this);
         if (agregar.Changed)
         {
             Actualiza();
         }
     }
 }
        private void btnEditarVariante_Click(object sender, EventArgs e)
        {
            if (materialListView2.SelectedItems.Count < 1)
            {
                return;
            }
            ProductoVariante variante = materialListView2.SelectedItems[0].Tag as ProductoVariante;

            using (EditarVarianteFrm agregar = new EditarVarianteFrm(tipo, variante))
            {
                agregar.ShowDialog(this);
                if (agregar.Changed)
                {
                    Actualiza();
                }
            }
        }