AbpVnext 本地事件总线

补充知识

发布订阅

概念

应用场景

本地事件总线允许服务发布和订阅进程内事件，这意味着如果两个服务>(发布者和订阅者)在同一个进程中运行，那么它是合适的

完整示例
DDD开发规范: 先定义好接口层、后实现层、暴露接口

对于要更新的实体

//领域层的实体 public class Book : FullAuditedEntity<Guid>, IHasExtraProperties, IMultiTenant {    public string Name{get;set;}     public string Author {get;set;}     public long Price {get;set}        public string Title {get;set;}     public string Classify{get;set;}     //条形码    public string BarCode {get;set;}    // 出版商    public string Issue{get;set;}    // 页数    public string PageTotal{get;set;}       public string BuyerId{get;set;}     public DateTime? ModifyTime{get;set} } 

//这个实体是必须有的 public class BookRecordEto{      public string Name{get;set;}      public string Author {get;set;}      public long Price {get;set}      public DateTime? ModifyTime{get;set} } 

//发布事件 public class BookService: ITransientDependency {     //Abp使用了字典来保存对实例的引用     public IAbpLazyServiceProvider LazyServiceProvider { get; set; }      //按需注入     protected ILocalEventBus  LocalEventBus => LazyServiceProvider.LazyGetRequiredService<ILocalEventBus >();       //仓储--对应Book的数据库表     protected IBookRepository BookRepository => LazyGetRequiredService<IBookRepository>();      public async Task UpdateData(Guid id)     {         var book =  await BookRepository.FindAsync(x=>x.Id = id);         if (book == null){//不存在实体}         var updateEntity = await BookRepository.UpdateAsync(book);         if (updateEntity == null){//更新失败}                  //实体数据发生变更，发布事件         await LocalEventBus.PublishAsync(new BookEto(){             Name = book.Name;             Author = book.Author;             Price = book.Price;             ModifyTime = DateTime.Now;         });     }  } 

//订阅事件 using Volo.Abp.DependencyInjection; using Volo.Abp.EventBus; public class EventBusHandler: ApplicationService,       , ILocalEventHandler<BookRecordEto>        , ITransientDependency {     // 进行业务数据更新，比如要更新购买这边书读者记录     public IAbpLazyServiceProvider LazyServiceProvider{get;set;}       protected IBookBoughtRecordRepository BoughtRecordRepository => LazyServiceProvider.LazyGetRequiredService<IBookBoughtRecordRepository>();      [UnitOfWork]//这个特性以及方法头里面的virtual很重要     public async virtual Task HandleEventAsync(BookRecordEto eventData)     {         //获取购买记录         var record =  await  BoughtRecordRepository.GetQueryableAsync();          var recordList = await AsyncExecuter.ToListAsync(record);                  if(recordList.Count() != 0){              var boughtRecord  = ObjectMapper.Map(eventData, new BoughtRecord());             //插入一条数据             await BoughtRecordRepository.InsertAsync(boughtRecord);         }     } } 

总结