How to map EditModel to Command Messages?

问题:

Jimmy Bogard at Los Techies says that he maps his EditModel to Command Messages instead of mapping EditModel to DomainModel. Can anyone explain this further?

回答1:

I'd guess it'd be a version of the command pattern that performs the necessary manipulations on the relevant domain objects based on the supplied message. e.g. Something like

public PromoteEmployeeCommand : ICommand {
     private readonly PromotionMessage _message;
     private readonly IEmployeeRepository _repository;

     public PromoteEmployeeCommand(PromotionMessage message,
                                   IEmployeeRepository repository) {
          _message = message;
          _repository = repository;
     }

     public void Execute() {
          /* Get the employee, give them a rise etc... */
     }
}

The mapping from the edit model would resolve to a number of command messages that could be invoked as required (e.g. Give employee a rise, notify their manager, add a note for payroll etc).

The advantage of this approach is that it can isolate your domain model from any presentational concerns exposed by the Edit model.