EndEventHandler Delegate
.NET Framework 3.0
Represents the method that handles asynchronous events such as application events.
Namespace: System.Web
Assembly: System.Web (in system.web.dll)
Assembly: System.Web (in system.web.dll)
'Declaration Public Delegate Sub EndEventHandler ( _ ar As IAsyncResult _ ) 'Usage Dim instance As New EndEventHandler(AddressOf HandlerMethod)
/** @delegate */ public delegate void EndEventHandler ( IAsyncResult ar )
Not applicable.
Parameters
- ar
The IAsyncResult that is the result of the BeginEventHandler operation.
This delegate is called by the event source when completion of the asynchronous operation is signaled by a callback to the BeginEventHandler delegate.
When you create an EndEventHandler 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 Events and Delegates.
The following code example uses the EndEventHandler delegate to register a handler for an asynchronous page.
<%@ page language="VB" Async="true"%> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <script runat="server"> Dim myRequest As System.Net.WebRequest Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Label1.Text = "Page_Load: Thread #" & System.Threading.Thread.CurrentThread.GetHashCode() Dim bh As New BeginEventHandler(AddressOf Me.BeginGetAsyncData) Dim eh As New EndEventHandler(AddressOf Me.EndGetAsyncData) Me.AddOnPreRenderCompleteAsync(bh, eh) ' Initialize the WebRequest object. Dim address As String address = "http://localhost/" myRequest = System.Net.WebRequest.Create(address) End Sub Function BeginGetAsyncData(ByVal src As Object, ByVal args As EventArgs, ByVal cb As AsyncCallback, ByVal state As Object) As IAsyncResult Label2.Text = "BeginGetAsyncData: Thread #" & System.Threading.Thread.CurrentThread.GetHashCode() Return Me.myRequest.BeginGetResponse(cb, state) End Function Sub EndGetAsyncData(ByVal ar As IAsyncResult) Label3.Text = "EndGetAsyncData: Thread #" & System.Threading.Thread.CurrentThread.GetHashCode() Dim myResponse As System.Net.WebResponse myResponse = Me.myRequest.EndGetResponse(ar) Dim reader As New System.IO.StreamReader(myResponse.GetResponseStream()) result.Text = reader.ReadToEnd() myResponse.Close() End Sub </script> <html xmlns="http://www.w3.org/1999/xhtml" > <head runat="server"> <title> Page.AddOnPreRenderCompleteAsync Example</title> </head> <body> <form id="form1" runat="server"> <asp:label id="Label1" runat="server"> Label 1</asp:label><br /> <asp:label id="Label2" runat="server"> Label 2</asp:label><br /> <asp:label id="Label3" runat="server"> Label 3</asp:label><br /> <asp:textbox id="result" runat="server" textMode="multiLine" ReadOnly="true" columns="80" rows="25" /> </form> </body> </html>
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