BeginEventHandler Delegate
Represents the method that handles asynchronous events such as application events. This delegate is called at the start of an asynchronous operation.
Assembly: System.Web (in System.Web.dll)
public delegate IAsyncResult^ BeginEventHandler( Object^ sender, EventArgs^ e, AsyncCallback^ cb, Object^ extraData )
Parameters
- sender
-
Type:
System::Object^
The source of the event.
- e
-
Type:
System::EventArgs^
An EventArgs that contains the event data.
- cb
-
Type:
System::AsyncCallback^
The delegate to call when the asynchronous method call is complete. If cb is null, the delegate is not called.
- extraData
-
Type:
System::Object^
Any additional data needed to process the request.
Return Value
Type: System::IAsyncResult^The IAsyncResult that represents the result of the BeginEventHandler operation.
When you create a BeginEventHandler delegate, you identify the method that will handle the event. To associate the event with your event handler, add an instance of the delegate to the event. The event handler is called whenever the event occurs, unless you remove the delegate. For more information about event-handler delegates, see NIB: Events and Delegates.
The following code example uses the BeginEventHandler delegate to register a handler an asynchronous page.
Security Note
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This example has a text box that accepts user input, which is a potential security threat. By default, ASP.NET Web pages validate that user input does not include script or HTML elements. For more information, see Script Exploits Overview. |
Available since 1.1
