2013-03-03 42 views
8

başarıyla ASP.NET Web Formları sayfalarında async void yöntemi kullandık. Bir web kullanıcı denetimi aynı yöntemi kullanın ve sonra async="true" ayarıyla bir sayfaya bu web kullanıcı denetimi koymak için çalıştım, ancak, bu hatayı almaya devam:ASP.NET kullanıcı denetiminde uyumsuz yöntem kullanılabilir mi?

An asynchronous operation cannot be started at this time. Asynchronous operations may only be started within an asynchronous handler or module or during certain events in the Page lifecycle. If this exception occurred while executing a Page, ensure that the Page is marked <%@ Page Async="true" %>.

Soru yani void async can yöntem, web kullanıcısı denetiminde kullanılmalı ve eşzamansız bir web formu sayfasına katıştırılmış mı? bir sayfada ise

cevap

6

Bir kontrol çağrı zaman uyumsuz yöntemleri olabilir.

Page.aspx Page.aspx arasında codebehind

Codebehind

<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="Control.ascx.cs" Inherits="AsyncDEmo.Control" %> 

<span id="TaskMessage" runat="server"> 
     </span> 

Kontrol

Control.ascx Boş

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Page.aspx.cs" Inherits="AsyncDEmo.Page" Async="true" %> 

<%@ Register Src="~/Control.ascx" TagPrefix="uc1" TagName="Control" %> 

<!DOCTYPE html> 

<html xmlns="http://www.w3.org/1999/xhtml"> 
<head runat="server"> 
    <title></title> 
</head> 
<body> 
    <form id="form1" runat="server"> 
     <uc1:Control runat="server" id="Control" /> 
    </form> 
</body> 
</html> 

: Bu örneğe bakın

protected void Page_Load(object sender, EventArgs e) 
    { 
     // Define the asynchronuous task. 
     Samples.AspNet.CS.Controls.SlowTask slowTask1 = 
      new Samples.AspNet.CS.Controls.SlowTask(); 
     Samples.AspNet.CS.Controls.SlowTask slowTask2 = 
     new Samples.AspNet.CS.Controls.SlowTask(); 
     Samples.AspNet.CS.Controls.SlowTask slowTask3 = 
     new Samples.AspNet.CS.Controls.SlowTask(); 

     PageAsyncTask asyncTask1 = new PageAsyncTask(slowTask1.OnBegin, slowTask1.OnEnd, slowTask1.OnTimeout, "Async1", true); 
     PageAsyncTask asyncTask2 = new PageAsyncTask(slowTask2.OnBegin, slowTask2.OnEnd, slowTask2.OnTimeout, "Async2", true); 
     PageAsyncTask asyncTask3 = new PageAsyncTask(slowTask3.OnBegin, slowTask3.OnEnd, slowTask3.OnTimeout, "Async3", true); 

     // Register the asynchronous task. 
     Page.RegisterAsyncTask(asyncTask1); 
     Page.RegisterAsyncTask(asyncTask2); 
     Page.RegisterAsyncTask(asyncTask3); 

     // Execute the register asynchronous task. 
     Page.ExecuteRegisteredAsyncTasks(); 

     TaskMessage.InnerHtml = slowTask1.GetAsyncTaskProgress() + "<br />" + slowTask2.GetAsyncTaskProgress() + "<br />" + slowTask3.GetAsyncTaskProgress(); 
    } 

SlowClass.cs

public class SlowTask 
{ 
    private String _taskprogress; 
    private AsyncTaskDelegate _dlgt; 

    // Create delegate. 
    protected delegate void AsyncTaskDelegate(); 

    public String GetAsyncTaskProgress() 
    { 
     return _taskprogress; 
    } 
    public void ExecuteAsyncTask() 
    { 
     // Introduce an artificial delay to simulate a delayed 
     // asynchronous task. 
     Thread.Sleep(TimeSpan.FromSeconds(5.0)); 
    } 

    // Define the method that will get called to 
    // start the asynchronous task. 
    public IAsyncResult OnBegin(object sender, EventArgs e, 
     AsyncCallback cb, object extraData) 
    { 
     _taskprogress = "AsyncTask started at: " + DateTime.Now + ". "; 

     _dlgt = new AsyncTaskDelegate(ExecuteAsyncTask); 
     IAsyncResult result = _dlgt.BeginInvoke(cb, extraData); 

     return result; 
    } 

    // Define the method that will get called when 
    // the asynchronous task is ended. 
    public void OnEnd(IAsyncResult ar) 
    { 
     _taskprogress += "AsyncTask completed at: " + DateTime.Now; 
     _dlgt.EndInvoke(ar); 
    } 

    // Define the method that will get called if the task 
    // is not completed within the asynchronous timeout interval. 
    public void OnTimeout(IAsyncResult ar) 
    { 
     _taskprogress += "AsyncTask failed to complete " + 
      "because it exceeded the AsyncTimeout parameter."; 
    } 
} 
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