Question

我正在尝试开发一个通用类来引发事件。

在运行时，我不知道会有什么实体，这就是为什么我决定使其通用。问题是，可以存在的每个单一类型都从基类EntityBase

继承

在此类中，我以正确的类型返回（或我想：P）事件。

public class EntityModifiedEventFactory<TEntity> : IEntityModifiedEventFactory<TEntity> where TEntity : EntityBase
{
    private readonly IEventAggregator eventAggregator;

    public EntityModifiedEventFactory(IEventAggregator eventAggregator)
      {
         ParameterChecker.IsNotNull(eventAggregator, "eventAggregator");

         this.eventAggregator = eventAggregator;
      }

    public EntityModifiedEvent<TEntity> Create()
      {
         return this.eventAggregator.GetEvent<EntityModifiedEvent<TEntity>>();
      }
}

在这里我调用构造函数，然后发布事件（不进行编译）

private void OnNotifyAgentEntityChanged(object sender, EntityChangedEventArgs entityChangedEventArgs)
{
    ViewModelIdentifierEventArgs<entityChangedEventArgs.Entity.GetType()> eventArgs = new ViewModelIdentifierEventArgs<entityChangedEventArgs.Entity.GetType() > (entityChangedEventArgs.ViewModelIdentifier, (entityChangedEventArgs.Entity.GetType())entityChangedEventArgs.Entity);

    IEntityModifiedEventFactory<entityChangedEventArgs.Entity.GetType() > entityModifiedEventFactory = new EntityModifiedEventFactory<entityChangedEventArgs.Entity.GetType()> ((entityChangedEventArgs.Entity.GetType())entityChangedEventArgs.Entity, this.eventAggregator);
    EntityModifiedEvent<entityChangedEventArgs.Entity.GetType()> entityModifiedEvent = entityModifiedEventFactory.Create();

    entityModifiedEvent.Publish(eventArgs);
}

我应该如何编写特定的类型来构建我的EntityModifiedEventFactory？。我尝试了此entityChangedEventArgs.Entity.GetType()，但无法使其正常工作。

如果我将TEntity上的IEntityModifiedEventFactory<TEntity> entityModifiedEventFactory...留为EntityBase，而我需要将其设为Animal或Tree类型，就像我一样表示从EntityBase

继承

这是可行的，但我需要将Tree的类型更改为来自EntityChangedEventArgs.Entity的任何类型：

        ViewModelIdentifierEventArgs<Tree> eventArgs = new ViewModelIdentifierEventArgs<Tree>(entityChangedEventArgs.ViewModelIdentifier, (Tree)entityChangedEventArgs.Entity);

        IEntityModifiedEventFactory<Tree> entityModifiedEventFactory = new EntityModifiedEventFactory<Tree> ((Tree)entityChangedEventArgs.Entity, this.eventAggregator);
        EntityModifiedEvent<Tree> entityModifiedEvent = entityModifiedEventFactory.Create();

        entityModifiedEvent.Publish(eventArgs);

Answer 1

我终于设法解决了这个问题。所以这是万一有人经历像我一样的事情的答案：

    private void OnNotifyAgentEntityChanged(object sender, EntityChangedEventArgs entityChangedEventArgs)
    {
        this.PublishEvent((TEntity)entityChangedEventArgs.Entity);
    }

    private void PublishEvent(TEntity entity)
    {
        object args = this.GetEventArgs(entity);
        object eventObject = this.GetEventObject(entity);

        MethodInfo publishMethod = eventObject.GetType().GetMethod("Publish");
        publishMethod.Invoke(eventObject, new[] { args });
    }

    private object GetEventArgs(TEntity entity)
    {
        Type viewModelIdentifierEventArgsType = typeof(ViewModelIdentifierEventArgs<>).MakeGenericType(entity.GetType());
        object args = Activator.CreateInstance(viewModelIdentifierEventArgsType, Guid.NewGuid(), entity);

        return args;
    }

    private object GetEventObject(TEntity entity)
    {
        MethodInfo getEventMethod = typeof(IEventAggregator).GetMethod("GetEvent");
        Type entityModifiedEventType = typeof(EntityModifiedEvent<>).MakeGenericType(entity.GetType());
        MethodInfo genericGetEventMethod = getEventMethod.MakeGenericMethod(entityModifiedEventType);
        object eventObject = genericGetEventMethod.Invoke(this.eventAggregator, null);

        return eventObject;
    }

通过此操作，我可以发布任何EntityModifiedEvent<>，而无需考虑TEntity。我只需要在KnownType中添加EntityChangedEventArgs，以便可以对其进行反序列化/序列化

通用发布事件类

1 个答案: