HttpResponse.AddOnSendingHeaders(Action<HttpContext>) 方法

定義

註冊 ASP.NET 執行階段會立即在回應標頭傳送給這個要求之前叫用的回呼。Registers a callback that the ASP.NET runtime will invoke immediately before response headers are sent for this request.

public:
 System::Web::ISubscriptionToken ^ AddOnSendingHeaders(Action<System::Web::HttpContext ^> ^ callback);
public System.Web.ISubscriptionToken AddOnSendingHeaders (Action<System.Web.HttpContext> callback);
member this.AddOnSendingHeaders : Action<System.Web.HttpContext> -> System.Web.ISubscriptionToken
Public Function AddOnSendingHeaders (callback As Action(Of HttpContext)) As ISubscriptionToken

參數

callback
Action<HttpContext>

回呼方法。The callback method.

傳回

ISubscriptionToken

ISubscriptionToken 物件,代表 OnSendingHeaders 虛擬事件的訂閱。An ISubscriptionToken object that represents the subscription to the OnSendingHeaders pseudo-event.

備註

重要

如果原生模組先排清回應,則不會叫用 AddOnSendingHeaders 方法。The AddOnSendingHeaders method is not invoked if the native module flushes the response first.

虛擬事件 OnSendingHeaders 與 IHttpModule 層級管線事件不同,因為它是每個要求的訂用帳戶,而不是每個應用程式的訂用帳戶。The pseudo-event OnSendingHeaders differs from the IHttpModule-level pipeline event in that it is a per-request subscription rather than a per-application subscription. 其目的是回呼可能會修改回應狀態碼,或可能設定回應 cookie 或標頭。The intent is that the callback may modify the response status code or may set a response cookie or header. 其他使用注意事項和注意事項:Other usage notes and caveats:

  • 只有當 IIS 在整合式管線模式管線中執行,而且只有在尚未傳送目前要求的回應標頭時,此方法才會生效。This method is effective only when IIS runs in integrated pipeline mode pipeline and only if response headers haven't yet been sent for the current request.

  • ASP.NET 執行時間不保證叫用回呼的任何相關執行緒。The ASP.NET runtime does not guarantee anything about the thread that the callback is invoked on. 例如,如果正在執行背景排清,則會在背景執行緒中以同步方式叫用回呼。For example, the callback may be invoked synchronously in a background thread if a background flush is being performed. Current 不保證可在這類執行緒中使用。Current is not guaranteed to be available in such a thread.

  • 回呼不能呼叫任何操作回應實體主體或導致排清的方法。The callback must not call any method that manipulates the response entity body or that results in a flush. 例如,回呼不能呼叫 Redirect ,因為該方法可能會操作回應實體主體。For example, the callback must not call Redirect, as that method may manipulate the response entity body.

  • 回呼必須只包含短時間執行的同步程式碼。The callback must contain only short-running synchronous code. 嘗試叫用非同步作業或等候這類作業時,可能會產生鎖死。Attempting to invoke an asynchronous operation or wait on such an operation could result in a deadlock.

  • 回呼不能擲回例外狀況;否則行為未定義。The callback must not throw an exception; otherwise behavior is undefined.

適用於