C＃事件，通過自定義的參數傳遞給處理程序

Question

進出口尋找一個方式做這樣的事情

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 
} 

因此需要處理的事件，重視處理它的方法，傳遞事件參數給這個函數加上一些另外還有一些參數。

我需要，因爲事件處理程序被添加不止一次這樣做那樣，我需要從處理方法觸發後，將其刪除的好。

我該怎麼做？

Answer 1

一個解決方案，我可以建議現在

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 
} 

---

編輯你的問題，我意識到，你仍然可以有一個命名的方法，如果你喜歡（但局部變量得到反正捕獲）

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，你需要定義一個代表事件處理程序的委託地方：

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

那麼對於OnFooDownloadEvent事件成員，則需要使用委託來定義：

public event FooDownloadEventHandler; 

訂閱就像你在你的例子代碼做的事件。

我希望這是你要找的人....

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

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