PageAsyncTask.BeginHandler 屬性

參考

定義

命名空間:: System.Web.UI

組件:: System.Web.dll

重要

部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。

取得當開始非同步工作時所要呼叫的方法。

public:
 property System::Web::BeginEventHandler ^ BeginHandler { System::Web::BeginEventHandler ^ get(); };

public System.Web.BeginEventHandler BeginHandler { get; }

member this.BeginHandler : System.Web.BeginEventHandler

Public ReadOnly Property BeginHandler As BeginEventHandler

屬性值

BeginEventHandler

BeginEventHandler 委派，表示當開始非同步工作時所要呼叫的方法。

範例

下列程式碼範例會向頁面註冊三個非同步工作，並平行執行它們。每個工作都會呼叫只讓執行緒睡眠 5 秒的方法。 BeginHandler每個工作都會指定委派。

<%@ Page Language="C#" Async="true" AsyncTimeout="35"%>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
    
  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();
    
    // <Snippet3> 
    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);
    // </Snippet3>
      
    // Execute the register asynchronous task.
    Page.ExecuteRegisteredAsyncTasks();

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

  }
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
    <title>Asynchronous Task Example</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
      <span id="TaskMessage" runat="server">
      </span>
    </div>
    </form>
</body>
</html>

<%@ Page Language="VB" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">
    Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
      
        ' Define the asynchronuous task.
        Dim slowTask1 As New Samples.AspNet.VB.Controls.SlowTask()
        Dim slowTask2 As New Samples.AspNet.VB.Controls.SlowTask()
        Dim slowTask3 As New Samples.AspNet.VB.Controls.SlowTask()
     
        ' <Snippet3>
        Dim asyncTask1 As New PageAsyncTask(AddressOf slowTask1.OnBegin, AddressOf slowTask1.OnEnd, AddressOf slowTask1.OnTimeout, "Async1", True)
        Dim asyncTask2 As New PageAsyncTask(AddressOf slowTask2.OnBegin, AddressOf slowTask2.OnEnd, AddressOf slowTask2.OnTimeout, "Async2", True)
        Dim asyncTask3 As New PageAsyncTask(AddressOf slowTask3.OnBegin, AddressOf slowTask3.OnEnd, AddressOf slowTask3.OnTimeout, "Async3", True)

        ' Register the asynchronous task.
        Page.RegisterAsyncTask(asyncTask1)
        Page.RegisterAsyncTask(asyncTask2)
        Page.RegisterAsyncTask(asyncTask3)
        ' </Snippet3>
      
        ' Execute the register asynchronous task.
        Page.ExecuteRegisteredAsyncTasks()

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

    End Sub
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>Untitled Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
    <span id="TaskMessage" runat="server">
      </span>
    </div>
    </form>
</body>
</html>

using System;
using System.Web;
using System.Web.UI;
using System.Threading;

namespace Samples.AspNet.CS.Controls
{
    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.";
        }
    }
}

Imports System.Threading

Namespace Samples.AspNet.VB.Controls

    Public Class SlowTask
        Private _taskprogress As String
        Private _dlgt As AsyncTaskDelegate

        ' Create delegate.
        Protected Delegate Sub AsyncTaskDelegate()

        Public Function GetAsyncTaskProgress() As String
            Return _taskprogress
        End Function

        Public Sub ExecuteAsyncTask()
            ' Introduce an artificial delay to simulate a delayed 
            ' asynchronous task.
            Thread.Sleep(TimeSpan.FromSeconds(5.0))
        End Sub

        ' Define the method that will get called to
        ' start the asynchronous task.
        Public Function OnBegin(ByVal sender As Object, ByVal e As EventArgs, ByVal cb As AsyncCallback, ByVal extraData As Object) As IAsyncResult
            _taskprogress = "AsyncTask started at: " + DateTime.Now.ToString + ". "

            _dlgt = New AsyncTaskDelegate(AddressOf ExecuteAsyncTask)
            Dim result As IAsyncResult = _dlgt.BeginInvoke(cb, extraData)

            Return result
        End Function

        ' Define the method that will get called when
        ' the asynchronous task is ended.
        Public Sub OnEnd(ByVal ar As IAsyncResult)
            _taskprogress += "AsyncTask completed at: " + DateTime.Now.ToString
            _dlgt.EndInvoke(ar)
        End Sub


        ' Define the method that will get called if the task
        ' is not completed within the asynchronous timeout interval.
        Public Sub OnTimeout(ByVal ar As IAsyncResult)
            _taskprogress += "AsyncTask failed to complete " + _
                "because it exceeded the AsyncTimeout parameter."
        End Sub
    End Class
End Namespace

備註

委派是在建 BeginHandler 構函式中設定。

適用於

共用方式為

PageAsyncTask.BeginHandler 屬性

定義

屬性值

範例

備註

適用於

其他資源