Question

I’m looking for a good way, or at least some insight, on how to cleanly report back progress to the UI layer.

My situation is as follows: I got a Repository in the Infrastructure Layer which communicates with the Data Layer. While those two are working the UI has currently no clue on what is going on and only passively waits for results (using an Observable)

My first thoughts were to expose events in the Repository to which the UI binds. But I feel that this can get quite messy. I would love to hear how you guys have solved this.

Answer 1

Uese either events or (bare) delegates.

Since you probably have multiple calls a delegate parameter might be best (not having to unregister from events).

// Repository
public delegate void ReportProgress(int percentage);

  public IEnumerable<X> GetSomeRecords(..., ReportProgress reporter)
  {
      ...;
      if (reporter != null)
          reporter(i * 100 / totalRecords);  
  }