C＃事件，通过自定义的参数传递给处理程序

Question

进出口寻找一个方式做这样的事情

public void Download(string oid) 
{ 
    Foo foo = Controller.Instance.GetFormation(oid); 
    Request request = new Request (data); 
    HttpResponseAction.Instance.OnFooDownloadedEvent += OnDoneDownloadAction(sender, event, request, foo); 
} 

private void OnDoneDownloadAction(object sender, OnLoadingEventArgs e, Request request, Foo foo) 
{ 
     // Do something with my awesome args 
} 

因此需要处理的事件，重视处理它的方法，传递事件参数给这个函数加上一些另外还有一些参数。

我需要，因为事件处理程序被添加不止一次这样做那样，我需要从处理方法触发后，将其删除的好。

我该怎么做？

Answer 1

一个解决方案，我可以建议现在

public void Download(string oid) 
{ 
    Foo foo = Controller.Instance.GetFormation(oid); 
    Request request = new Request (data); 

    // create a local variable of required delegate type 
    EventHandler<OnLoadingEventArgs> handler = 
    (object sender, OnLoadingEventArgs ev) => 
    { 
     // foo and request can be used here 
     // if foo or request is used here, then it became captured variable 

     // Do something with your awesome captured variables: foo and request 
    }; 

    // subscribe to event 
    HttpResponseAction.Instance.OnFooDownloadedEvent += handler; 

    // unsubscribe event handler when necessary 
    HttpResponseAction.Instance.OnFooDownloadedEvent -= handler; 
    // you might want to return handler from method or store it somewhere 
} 

---

编辑你的问题，我意识到，你仍然可以有一个命名的方法，如果你喜欢（但局部变量得到反正捕获）

public void Download(string oid) 
{ 
    Foo foo = Controller.Instance.GetFormation(oid); 
    Request request = new Request (data); 

    // create a local variable of required delegate type 
    EventHandler<OnLoadingEventArgs> handler = 
    (object sender, OnLoadingEventArgs ev) => 
    OnDoneDownloadAction(sender, ev, request, foo); 

    // subscribe to event 
    HttpResponseAction.Instance.OnFooDownloadedEvent += handler; 

    // unsubscribe event handler when necessary 
    HttpResponseAction.Instance.OnFooDownloadedEvent -= handler; 
    // you might want to return handler from method or store it somewhere 
} 

private void OnDoneDownloadAction(object sender, OnLoadingEventArgs e, Request request, Foo foo) 
{ 
     // Do something with my awesome args 
} 

Answer 2

首先，你需要定义一个代表事件处理程序的委托地方：

// This needs to be inside a namespace... 
public delegate void FooDownloadEventHandler(object sender, OnLoadingEventArgs e, Request request, Foo foo); 

那么对于OnFooDownloadEvent事件成员，则需要使用委托来定义：

public event FooDownloadEventHandler; 

订阅就像你在你的例子代码做的事件。

我希望这是你要找的人....

https://msdn.microsoft.com/en-us/library/ms173171.aspx

https://msdn.microsoft.com/en-us/library/8627sbea.aspx