void MontoIvaCalcEdit_Validating(object sender, CancelEventArgs e)
 {
     DevExpress.XtraEditors.CalcEdit editor = (DevExpress.XtraEditors.CalcEdit)sender;
     //if (!editor.IsModified)
     //    return;
     this.libroCompraBindingSource.EndEdit();
     registro.Calcular();
 }
 private void Aceptar_Click(object sender, EventArgs e)
 {
     try
     {
         libroCompraBindingSource.EndEdit();
         registro = (LibroCompra)libroCompraBindingSource.Current;
         registro.Calcular();
         this.DialogResult = DialogResult.OK;
         this.Close();
     }
     catch (Exception ex)
     {
         MessageBox.Show("Error al validar los datos \n" + ex.Message, "Atencion", MessageBoxButtons.OK);
     }
 }