// Apply the deltas to mutate our state
private void Apply(LineItemAdded @event)
{
var price = @event.Price * (1 + @event.Vat / 100);
Total += price;
lines.Add(Tuple.Create(@event.Description, price, @event.Vat));
// Ensure to update version on every Apply method.
Version++;
}
// Enforce any contracts on input, then raise event capturing the data
public void AddLine(decimal price, decimal vat, string description)
{
if (string.IsNullOrEmpty(description))
{
throw new ArgumentException("Description cannot be empty", nameof(description));
}
var @event = new LineItemAdded(price, vat, description);
// Call Apply to mutate state of aggregate based on event
Apply(@event);
// Add the event to uncommitted events to use it while persisting the events to Marten events store
AddUncommittedEvent(@event);
}