如何使用Autofac的方法关联事件？ [英] How to wire events with methods using Autofac?

问题描述

是否可以通过接口/类（通过构造函数和属性注入）将事件连接到具有Autofac的方法，而不是整个对象。我想在功能级别而不是类型级别进行绑定。我以编程方式希望完成以下工作（在C＃中）：

  someType.Output + = someOtherType.Input; 
  

例如，Spring.net确实支持以下构造来实现：

 < object id = SomeType type = Whatever.SomeType，Whatever /> 
< object id = SomeOtherType type = Whatever.SomeOtherType，无论如何> 
< listener event = Output method = Input> 
< ref object = SomeType /> 
< / listener> 
< / object> 
  

Autofac能够做到吗？如何做到？

解决方案

我假设您的对象在一起没有直接依赖关系，例如：

 公共类SomeType 
 {
 public event EventHandler Input; 
 
 public void Raise（）
 {
 if（Input！= null）
 {
 Input（this，new EventArgs（））; 
} 
} 
} 
 
公共类SomeOtherType 
 {
 public void输出（对象源，EventArgs处理程序）
 { 
 Console.WriteLine（ Handled）; 
} 
} 
  

您可以使用激活或绑定委托： / p>

已激活：

  ContainerBuilder cb = new ContainerBuilder（）; 
 
 cb.RegisterType< SomeOtherType>（）; 
 cb.RegisterType< SomeType>（）
 .OnActivated（act => 
 {
 var other = act.Context.Resolve< SomeOtherType>（）; 
 act.Instance.Input + = other.Output; 
}）; 
 var container = cb.Build（）; 
 
 var obj2 = container.Resolve< SomeType>（）; 
 obj2.Raise（）; 
  

代理版本，将注册替换为：

  cb.Register（ctx => 
 {
 var other = ctx.Resolve< SomeOtherType>（）; 
 var obj = new SomeType（） ; 
 obj.Input + = other.Output; 
 return obj; 
}）。As< SomeType>（）; 
  

请注意，进行这种类型的绑定有时会有些危险（当您创建一个

创建一个附加两个元素并实现IDisposable的小型类，以便在不再需要时取消注册事件可能是明智的选择。

>

我认为不可能通过xml配置来关联事件，对于这种类型的绑定，我更喜欢代码提供的编译时安全性，但是也许您有一个xml用例。

Is it possible to wire events to methods with Autofac instead of whole object via interfaces/classes (through constructor and property injection). I want to bind at function level instead of type level. Programmatically I expect the following job to be done (in C#):

someType.Output += someOtherType.Input;

For example Spring.net does support the following construct to achieve that:

<object id="SomeType" type="Whatever.SomeType, Whatever" />
<object id="SomeOtherType" type="Whatever.SomeOtherType, Whatever">
  <listener event="Output" method="Input">
    <ref object="SomeType" />
  </listener>
</object>

Is Autofac able to do that and how? Is it possible to use xml config for such a task?

解决方案

I assume that you objects have no direct dependency together, like :

    public class SomeType
{
    public event EventHandler Input;

    public void Raise()
    {
        if (Input != null)
        {
            Input(this, new EventArgs());
        }
    }
}

public class SomeOtherType
{      
    public void Output(object source, EventArgs handler)
    {
        Console.WriteLine("Handled");
    }
}

You can either use Activated or bind a delegate:

Activated:

        ContainerBuilder cb = new ContainerBuilder();

        cb.RegisterType<SomeOtherType>();
        cb.RegisterType<SomeType>()
            .OnActivated(act => 
            { 
                var other = act.Context.Resolve<SomeOtherType>(); 
                act.Instance.Input += other.Output; 
            });
        var container = cb.Build();

        var obj2 = container.Resolve<SomeType>();
        obj2.Raise();

Delegate version, replace registration by:

        cb.Register(ctx =>
        {
            var other = ctx.Resolve<SomeOtherType>();
            var obj = new SomeType();
            obj.Input += other.Output;
            return obj;
        }).As<SomeType>();

As a side note, doing this type of binding can sometimes be a bit dangerous (as you create an event dependency) and create memory leak.

Creating a small class that attach both elements and implement IDisposable to unregister event when not needed anymore could be a sensible option.

I don't think it is possible to wire events via xml configuration, and for this type of binding I would largely prefer the compile time safety offered by code, but maybe you have a use case for xml.

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