Triggers and traits (e.g. SoftDelete)

Triggers are not restricted for entity types only but can also be defined for base classes or even interfaces. Consider that we want to implement soft delete using triggers:

public interface ISoftDelete {
    DateTime? DeletedOn { get; set; } 
}

public class EnsureSoftDeletedTrigger : IBeforeSaveTrigger<ISoftDelete>
{
    readonly IApplicationDbContext _applicationDbContext;

    public EnsureSoftDeletedTrigger(ApplicationDbContext applicationDbContext) {
        _applicationDbContext = applicationDbContext;
    }

    public Task BeforeSave(ITriggerContext<ISoftDelete> context, CancellationToken cancellationToken) {
        if (context.ChangeType == ChangeType.Deleted) {
            context.Entity.DeletedOn = DateTime.UtcNow;
            _applicationDbContext.Entry(context.Entity).State = Microsoft.EntityFrameworkCore.EntityState.Modified;
        }
    } 
}

Any entity that now implements the ISoftDelete interface will be soft-deleted.