要求：修改good表，添加 organization
基础定义
用于引发和调度事件的延迟方法 AddDomainEvent
Domain\SeedWork\Entity.cs
public abstract class Entity<T>
{
int? _requestedHashCode;
T _Id;
public virtual T Id
{
get
{
return _Id;
}
protected set
{
_Id = value;
}
} private List<INotification> _domainEvents;
public IReadOnlyCollection<INotification> DomainEvents => _domainEvents?.AsReadOnly(); public void AddDomainEvent(INotification eventItem)
{
_domainEvents = _domainEvents ?? new List<INotification>();
_domainEvents.Add(eventItem);
} public void RemoveDomainEvent(INotification eventItem)
{
_domainEvents?.Remove(eventItem);
} public void ClearDomainEvents()
{
_domainEvents?.Clear();
} public bool IsTransient()
{
return Id.ToString() == default(T).ToString();
} public override bool Equals(object obj)
{
if (obj == null || !(obj is Entity<T>))
return false; if (Object.ReferenceEquals(this, obj))
return true; if (this.GetType() != obj.GetType())
return false; Entity<T> item = (Entity<T>)obj; if (item.IsTransient() || this.IsTransient())
return false;
else
return item.Id.ToString() == this.Id.ToString();
} public override int GetHashCode()
{
if (!IsTransient())
{
if (!_requestedHashCode.HasValue)
_requestedHashCode = this.Id.GetHashCode() ^ 31; // XOR for random distribution (http://blogs.msdn.com/b/ericlippert/archive/2011/02/28/guidelines-and-rules-for-gethashcode.aspx) return _requestedHashCode.Value;
}
else
return base.GetHashCode(); }
public static bool operator ==(Entity<T> left, Entity<T> right)
{
if (Object.Equals(left, null))
return (Object.Equals(right, null)) ? true : false;
else
return left.Equals(right);
} public static bool operator !=(Entity<T> left, Entity<T> right)
{
return !(left == right);
}
}
聚合根
Goods.cs
public class Goods: Entity<Guid>, IAggregateRoot
{ public string CreatedBy { get; private set; }
public DateTime? CreatedTime { get; private set; } public string ModifiedBy { get; private set; } public DateTime? ModifiedTime { get; private set; } public string GoodsName { get; private set; }
public int? GoodsNum { get; private set; } public Goods(string createdBy, DateTime? createdTime, string modifiedBy, DateTime? modifiedTime, string goodsName, int? goodsNum)
{
CreatedBy = createdBy;
CreatedTime = createdTime;
ModifiedBy = modifiedBy;
ModifiedTime = modifiedTime;
GoodsName = goodsName;
GoodsNum = goodsNum;
} public void StockAddedToGoods()
{
AddDomainEvent(new StockAddedToGoodsDomainEvent()); //加入事件列表
} public void SetModified()
{
ModifiedBy = "aaaaa";
ModifiedTime = DateTime.Now;
}
}
请注意 AddDomainEvent 方法的唯一功能是将事件添加到列表。 尚未调度任何事件，尚未调用任何事件处理程序。
你需要在稍后将事务提交到数据库时调度事件。 如果使用 Entity Framework Core，意味着在 EF DbContext 的 SaveChanges 方法中，如以下示例所示：
// EF Core DbContext
public class SampleContext : DbContext, IUnitOfWork
{
// ...
public async Task<bool> SaveEntitiesAsync(CancellationToken cancellationToken = default(CancellationToken))
{
// Dispatch Domain Events collection.
// Choices:
// A) Right BEFORE committing data (EF SaveChanges) into the DB. This makes
// a single transaction including side effects from the domain event
// handlers that are using the same DbContext with Scope lifetime
// B) Right AFTER committing data (EF SaveChanges) into the DB. This makes
// multiple transactions. You will need to handle eventual consistency and
// compensatory actions in case of failures.
await _mediator.DispatchDomainEventsAsync(this); // After this line runs, all the changes (from the Command Handler and Domain
// event handlers) performed through the DbContext will be committed
var result = await base.SaveChangesAsync();
}
}
Organization.cs
public class Organization:
Entity<Guid>, IAggregateRoot
{
public string CreatedBy { get; set; }
public DateTime CreatedTime { get; set; }
public string ModifiedBy { get; set; }
public DateTime ModifiedTime { get; set; } public string Name { get; set; } private Organization() { } public Organization(Guid id, string name, string createdBy, DateTime createdTime, string modifiedBy,DateTime modifiedTime)
{
Id = id;
Name = name;
CreatedBy = createdBy;
ModifiedBy = modifiedBy;
ModifiedTime = modifiedTime; AddDomainEvent(new OrganizationCreatedDomainEvent(name, id));
} }
CQRS
1.创建命令
[DataContract]
public class UpdateGoodsAndAddStockCommand : IRequest<bool>
{
[DataMember]
public Guid Id { get; set; }
[DataMember]
public string CreatedBy { get; private set; } [DataMember]
public string GoodsName { get; private set; }
[DataMember]
public int GoodsNum { get; private set; }
}
2.创建处理
public class UpdateGoodsAndAddStockCommandHandler: IRequestHandler<UpdateGoodsAndAddStockCommand, bool>
{
private readonly IGoodsRepository _goodsRepository;
private readonly IMediator _mediator; public UpdateGoodsAndAddStockCommandHandler(IGoodsRepository goodsRepository, IMediator mediator)
{
_goodsRepository = goodsRepository;
_mediator = mediator;
} public async Task<bool> Handle(UpdateGoodsAndAddStockCommand request, CancellationToken cancellationToken)
{
var good = await _goodsRepository.GetAsync(request.Id); good.SetModified(); //赋值修改人和修改时间,
good.StockAddedToGoods(); //添加 Stock 事件
return await _goodsRepository.UnitOfWork.SaveEntitiesAsync();
}
}
3.使用 IoC 的域事件调度程序
public class MediatorModule : Autofac.Module
{
protected override void Load(ContainerBuilder builder)
{
builder.RegisterAssemblyTypes(typeof(IMediator).GetTypeInfo().Assembly)
.AsImplementedInterfaces(); // Register all the Command classes (they implement IRequestHandler) in assembly holding the Commands
builder.RegisterAssemblyTypes(typeof(CreateOrderCommand).GetTypeInfo().Assembly)
.AsClosedTypesOf(typeof(IRequestHandler<,>)); //这里
builder.RegisterAssemblyTypes(typeof(UpdateGoodsAndAddStockCommand).GetTypeInfo().Assembly)
.AsClosedTypesOf(typeof(IRequestHandler<,>)) // Other registrations ...
}
}
事件列表
Sample.Domain\Event\StockAddedToGoodsDomainEvent.cs
public class StockAddedToGoodsDomainEvent: INotification
{
public Organization Organization { get; } public StockAddedToGoodsDomainEvent()
{
Organization = new Organization(Guid.NewGuid(), "tss","tss", DateTime.Now,null,DateTime.Now);
}
}
事件处理：StockAddedToGoodsDomainEventHandler
public class StockAddedToGoodsDomainEventHandler : INotificationHandler<StockAddedToGoodsDomainEvent>
{
private readonly IOrganizationRepository _iorganizationRepository;
private readonly ILoggerFactory _logger;
private readonly ISampleIntegrationEventService _sampleIntegrationEventService; public StockAddedToGoodsDomainEventHandler(IOrganizationRepository iorganizationRepository, ILoggerFactory logger)
{
_iorganizationRepository = iorganizationRepository;
_logger = logger;
} public async Task Handle(Domain.Events.StockAddedToGoodsDomainEvent notification, CancellationToken cancellationToken)
{
_iorganizationRepository.Add(notification.Organization); var organization = await _iorganizationRepository.GetAsync(notification.Organization.Id);
await _iorganizationRepository.UnitOfWork.SaveEntitiesAsync();
_logger.CreateLogger(nameof(StockAddedToGoodsDomainEventHandler))
.LogTrace($"Stock with Id: {organization.Id} has been successfully Created");
}
}
资料：
microsoft.doc 域事件：设计和实现
