Reference:
Asynchronous programming of mcad learning notes (asynccallback delegation, iasyncresult interface, begininvoke method, and endinvoke method)
Http://www.cnblogs.com/aierong/archive/2005/05/25/162308.html
Delegated re-understanding of mcad learning notes (discussion of Delegate constructor, begininvoke, endinvoke, and invoke4 methods)
Http://www.cnblogs.com/aierong/archive/2005/05/25/162181.html
It's classic.Article. All at once solved my understanding of iasyncresult.
In fact, there are four asynchronous modes of ASP. NET, which can be implemented using the functions provided by iasyncresult flexibly. I will use the asynceventhandler proxy to complete all my asynchronous operations.
Core of the buffer layer Code : Public Delegate Void Asynceventhandler (); // Declare an asynchronous proxy
Public Class Connectionpipe
... {
Private Event Asynceventhandler asy; // Instantiate proxy
Private Contentfetcher fetcher; // Get data class
Public Iasyncresult begincalling (asynccallback CB, String Param)
... {
If (CB = Null )
Throw New Exception ( " Missing para! " );
If (Param = Null | Param = "" )
Throw New Exception ( " Missing para! " );
Fetcher = New Contentfetcher (pathmappingcontroller. instance. getpath (PARAM ));
Asy = New Asynceventhandler (Fetcher. Fetching );
Return Asy. begininvoke ( New Asynccallback (CB ), This );
}
Public Void Endcalling (iasyncresult AR)
... {
If(Asy= Null)
Throw NewException ("Run begincalling first!");
Asy. endinvoke (AR );
}
Public String Content
... {
Get ...{ReturnFetcher. content ;}
}
} Page code: Public Partial Class Subpages_03projects_lenovo: system. Web. UI. Page
... {
Protected String Pagecontent;
Protected Void Page_load ( Object Sender, eventargs E)
... {
Addonprerendercompleteasync (
NewBegineventhandler (beginasyncoperation ),
NewEndeventhandler (endasyncoperation)
);
}
Iasyncresult beginasyncoperation ( Object Sender, eventargs e,
Asynccallback CB, Object State)
... {
Connectionpipe Pipe= NewConnectionpipe ();
ReturnPipe. begincalling (CB,"Testme");
}
Void Endasyncoperation (iasyncresult AR)
... {
(AR. asyncstateAsConnectionpipe). endcalling (AR );
Pagecontent=(AR. asyncstateAsConnectionpipe). content;
}
} Thought :. Start the page and call connectionpipe asynchronously to obtain data .. When the data is obtained, the automatic call ends .. The asynchronous operations provided in the proxy are used: begininvoke and endinvoke, so that I do not need to implement the iasyncresult interface myself .. The proxy automatically calls asynccallback after the method operation is completed. This saves me a lot of trouble. Asp.net asynchronous learning is complete.
