Page.AddOnPreRenderCompleteAsync 方法

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。

為非同步頁面，註冊開始與結束事件處理常式委派。

多載

AddOnPreRenderCompleteAsync(BeginEventHandler, EndEventHandler)	為非同步頁面，註冊不需要狀態資訊的開始與結束事件處理常式委派。
AddOnPreRenderCompleteAsync(BeginEventHandler, EndEventHandler, Object)	為非同步頁面，註冊開始與結束事件處理常式委派。

AddOnPreRenderCompleteAsync(BeginEventHandler, EndEventHandler)

為非同步頁面，註冊不需要狀態資訊的開始與結束事件處理常式委派。

public:
 void AddOnPreRenderCompleteAsync(System::Web::BeginEventHandler ^ beginHandler, System::Web::EndEventHandler ^ endHandler);

public void AddOnPreRenderCompleteAsync (System.Web.BeginEventHandler beginHandler, System.Web.EndEventHandler endHandler);

member this.AddOnPreRenderCompleteAsync : System.Web.BeginEventHandler * System.Web.EndEventHandler -> unit

Public Sub AddOnPreRenderCompleteAsync (beginHandler As BeginEventHandler, endHandler As EndEventHandler)

參數

beginHandler: BeginEventHandler

BeginEventHandler 方法的委派。

endHandler: EndEventHandler

EndEventHandler 方法的委派。

例外狀況

InvalidOperationException

<async> 頁面指示詞未設定為 true。

-或-

在 AddOnPreRenderCompleteAsync(BeginEventHandler, EndEventHandler) 事件之後，呼叫 PreRender 方法。

ArgumentNullException

BeginHandler 或 EndHandler 為 null

範例

下列程式碼範例會使用非同步要求，在控制項中 TextBox 顯示本機網頁伺服器預設頁面的 HTML 原始程式碼。

重要

這個範例有一個可接受使用者輸入的文字方塊，這可能會造成安全性威脅。根據預設，ASP.NET Web 網頁會驗證使用者輸入未包含指令碼或 HTML 項目。如需詳細資訊，請參閱 Script Exploits Overview (指令碼攻擊概觀)。

<%@ page language="C#" 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">
  System.Net.WebRequest myRequest;

  void Page_Load(object sender, EventArgs e)
  {
    Label1.Text = "Page_Load: thread #" + System.Threading.Thread.CurrentThread.GetHashCode();

    BeginEventHandler bh = new BeginEventHandler(this.BeginGetAsyncData);
    EndEventHandler eh = new EndEventHandler(this.EndGetAsyncData);

    AddOnPreRenderCompleteAsync(bh, eh);

    // Initialize the WebRequest.
    string address = "http://localhost/";

    myRequest = System.Net.WebRequest.Create(address);
  }

  IAsyncResult BeginGetAsyncData(Object src, EventArgs args, AsyncCallback cb, Object state)
  {
    Label2.Text = "BeginGetAsyncData: thread #" + System.Threading.Thread.CurrentThread.GetHashCode();
    return myRequest.BeginGetResponse(cb, state);
  }

  void EndGetAsyncData(IAsyncResult ar)
  {
    Label3.Text = "EndGetAsyncData: thread #" + System.Threading.Thread.CurrentThread.GetHashCode();

    System.Net.WebResponse myResponse = myRequest.EndGetResponse(ar);

    result.Text = new System.IO.StreamReader(myResponse.GetResponseStream()).ReadToEnd();
    myResponse.Close();
  }

</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>

<%@ 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>

備註

AddOnPreRenderCompleteAsync使用方法可將處理常式新增至非同步網頁。

您可以註冊多個非同步處理常式;不過，一次只會執行一個處理常式。如果您想要同時處理多個非同步方法，您應該使用單 BeginEventHandler 一方法，並從該處理常式啟動多個非同步作業。

非同步處理常式會在和 PreRenderComplete 事件之間 PreRender 呼叫。

首先，會執行透過 PreRender 事件) (的所有 Page 事件，然後呼叫每個已註冊 BeginEventHandler 的方法。當處理常式完成時，會呼叫對應的 EndEventHandler 方法。如果有多個非同步處理常式，則會呼叫下一個處理常式。

呼叫已註冊的非同步事件處理常式之後，會從事件開始 PreRenderComplete 呼叫頁面事件的其餘部分。

另請參閱

適用於

AddOnPreRenderCompleteAsync(BeginEventHandler, EndEventHandler, Object)

為非同步頁面，註冊開始與結束事件處理常式委派。

public:
 void AddOnPreRenderCompleteAsync(System::Web::BeginEventHandler ^ beginHandler, System::Web::EndEventHandler ^ endHandler, System::Object ^ state);

public void AddOnPreRenderCompleteAsync (System.Web.BeginEventHandler beginHandler, System.Web.EndEventHandler endHandler, object state);

member this.AddOnPreRenderCompleteAsync : System.Web.BeginEventHandler * System.Web.EndEventHandler * obj -> unit

Public Sub AddOnPreRenderCompleteAsync (beginHandler As BeginEventHandler, endHandler As EndEventHandler, state As Object)

參數

beginHandler: BeginEventHandler

BeginEventHandler 方法的委派。

endHandler: EndEventHandler

EndEventHandler 方法的委派。

state: Object

物件，包含事件處理常式的狀態資訊。

例外狀況

InvalidOperationException

<async> 頁面指示詞未設定為 true。

-或-

在 AddOnPreRenderCompleteAsync(BeginEventHandler, EndEventHandler) 事件之後，呼叫 PreRender 方法。

ArgumentNullException

BeginHandler 或 EndHandler 為 null

範例

下列程式碼範例會使用非同步要求，在控制項中 TextBox 顯示本機網頁伺服器預設頁面的 HTML 原始程式碼。

重要

<%@ page language="C#" 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">
  System.Net.WebRequest myRequest;

  void Page_Load(object sender, EventArgs e)
  {
    Label1.Text = "Page_Load: thread #" + System.Threading.Thread.CurrentThread.GetHashCode();

    BeginEventHandler bh = new BeginEventHandler(this.BeginGetAsyncData);
    EndEventHandler eh = new EndEventHandler(this.EndGetAsyncData);

    AddOnPreRenderCompleteAsync(bh, eh);

    // Initialize the WebRequest.
    string address = "http://localhost/";

    myRequest = System.Net.WebRequest.Create(address);
  }

  IAsyncResult BeginGetAsyncData(Object src, EventArgs args, AsyncCallback cb, Object state)
  {
    Label2.Text = "BeginGetAsyncData: thread #" + System.Threading.Thread.CurrentThread.GetHashCode();
    return myRequest.BeginGetResponse(cb, state);
  }

  void EndGetAsyncData(IAsyncResult ar)
  {
    Label3.Text = "EndGetAsyncData: thread #" + System.Threading.Thread.CurrentThread.GetHashCode();

    System.Net.WebResponse myResponse = myRequest.EndGetResponse(ar);

    result.Text = new System.IO.StreamReader(myResponse.GetResponseStream()).ReadToEnd();
    myResponse.Close();
  }

</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>

<%@ 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>

備註

AddOnPreRenderCompleteAsync使用方法，將需要狀態資訊的處理常式新增至非同步網頁。傳入參數的物件 state 可以是應用程式在和 endHandler 參數中指定的 beginHandler 事件處理常式委派之間傳輸資訊所需的任何物件。

非同步處理常式會在和 PreRenderComplete 事件之間 PreRender 呼叫。

呼叫已註冊的非同步事件處理常式之後，會從事件開始 PreRenderComplete 呼叫頁面事件的其餘部分。

適用於

Page.AddOnPreRenderCompleteAsync 方法

定義

多載

AddOnPreRenderCompleteAsync(BeginEventHandler, EndEventHandler)

參數

例外狀況

範例

備註

另請參閱

適用於

AddOnPreRenderCompleteAsync(BeginEventHandler, EndEventHandler, Object)

參數

例外狀況

範例

備註

適用於

意見反應

其他資源