HtmlInputRadioButton.OnPreRender-Methode

Artikel
08/20/2007

Löst das PreRender-Ereignis aus und registriert das HtmlInputRadioButton-Steuerelement als ein Steuerelement, für das eine Postbackbehandlung erforderlich ist.

Namespace: System.Web.UI.HtmlControls
Assembly: System.Web (in system.web.dll)

Syntax

'Declaration
Protected Friend Overrides Sub OnPreRender ( _
    e As EventArgs _
)
'Usage
Dim e As EventArgs

Me.OnPreRender(e)

protected internal override void OnPreRender (
    EventArgs e
)

protected public:
virtual void OnPreRender (
    EventArgs^ e
) override

protected void OnPreRender (
    EventArgs e
)

protected internal override function OnPreRender (
    e : EventArgs
)

Parameter

e
Ein System.EventArgs, das die Ereignisdaten enthält.

Hinweise

Die OnPreRender-Methode wird kurz vor dem Rendern des HtmlInputRadioButton-Steuerelements aufgerufen.

Die OnPreRender-Methode wird hauptsächlich von Entwicklern von Steuerelementen zum Erweitern der Funktionalität des HtmlInputRadioButton-Steuerelements verwendet.

Beispiel

Im folgenden Codebeispiel wird das Überschreiben der OnPreRender-Methode veranschaulicht, sodass diese ein Title-Attribut in einem benutzerdefinierten HtmlInputRadioButton-Serversteuerelement hinzufügt.

<%@ Page Language="VB" AutoEventWireup="True" %>
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.VB.Controls" Assembly="Samples.AspNet.VB" %>
<HTML>
  <HEAD><title>Custom HtmlInputRadioButton - OnPreRender - Visual Basic Example</title>
    <script runat="server">
      Sub Page_Load(sender As Object, e As EventArgs)
        Div1.InnerHtml = ""
      End Sub

      Sub HtmlInputRadioButtonGroup1_ServerChange(sender As Object, e As System.EventArgs)
        Dim htmlInputRadioButtonGroup1 As System.Web.UI.HtmlControls.HtmlInputRadioButton  = CType(sender, System.Web.UI.HtmlControls.HtmlInputRadioButton)
        Div1.InnerHtml = "You change your selection to: " & htmlInputRadioButtonGroup1.Value
      End Sub
    </script>
  </HEAD>
  <body>
    <form id="Form1" method="post" runat="server">
      <h3>Custom HtmlInputRadioButton - OnPreRender - Visual Basic Example</h3>

      <aspSample:CustomHtmlInputRadioButtonOnPreRender 
        id="HtmlInputRadioButton1" 
        name="HtmlInputRadioButtonGroup1" 
        runat="server" 
        type="radio" checked
        onserverchange="HtmlInputRadioButtonGroup1_ServerChange" 
        value="HtmlInputRadioButton1">HtmlInputRadioButton1
      </aspSample:CustomHtmlInputRadioButtonOnPreRender>
      <br>

      <aspSample:CustomHtmlInputRadioButtonOnPreRender 
        id="HtmlInputRadioButton2" 
        name="HtmlInputRadioButtonGroup1" 
        runat="server" 
        type="radio" 
        onserverchange="HtmlInputRadioButtonGroup1_ServerChange" 
        value="HtmlInputRadioButton2">HtmlInputRadioButton2
      </aspSample:CustomHtmlInputRadioButtonOnPreRender>

      <p>
        <input type="submit" value="Submit" id="Submit1" name="Submit1" runat="server">
      </p>
      
      <DIV 
        id="Div1" 
        runat="server" 
        style="DISPLAY: inline; WIDTH: 256px; HEIGHT: 15px" 
        ms_positioning="FlowLayout" />
    </form>
  </body>
</HTML>

<%@ Page Language="C#" AutoEventWireup="True" %>
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS.Controls" Assembly="Samples.AspNet.CS" %>
<HTML>
  <HEAD><title>Custom HtmlInputRadioButton - OnPreRender - C# Example</title>
    <script runat="server">
      void Page_Load(Object sender, EventArgs e) 
      {
        Div1.InnerHtml = "";
      }

      void HtmlInputRadioButtonGroup1_ServerChange(object sender, System.EventArgs e)
      {
        // Diplay the value of the selected HtmlInputRadioButton control.
        System.Web.UI.HtmlControls.HtmlInputRadioButton htmlInputRadioButtonGroup1 = (System.Web.UI.HtmlControls.HtmlInputRadioButton) sender;
        Div1.InnerHtml = "You change your selection to: " + htmlInputRadioButtonGroup1.Value;
      }
    </script>
  </HEAD>
  <body>
    <form id="Form1" method="post" runat="server">
      <h3>Custom HtmlInputRadioButton - OnPreRender - C# Example</h3>

      <aspSample:CustomHtmlInputRadioButtonOnPreRender 
        id="HtmlInputRadioButton1" 
        name="HtmlInputRadioButtonGroup1" 
        runat="server" 
        type="radio" checked
        onserverchange="HtmlInputRadioButtonGroup1_ServerChange" 
        value="HtmlInputRadioButton1">HtmlInputRadioButton1
      </aspSample:CustomHtmlInputRadioButtonOnPreRender>
      <br>

      <aspSample:CustomHtmlInputRadioButtonOnPreRender 
        id="HtmlInputRadioButton2" 
        name="HtmlInputRadioButtonGroup1" 
        runat="server" 
        type="radio" 
        onserverchange="HtmlInputRadioButtonGroup1_ServerChange" 
        value="HtmlInputRadioButton2">HtmlInputRadioButton2
      </aspSample:CustomHtmlInputRadioButtonOnPreRender>

      <p>
        <input type="submit" value="Submit" id="Submit1" name="Submit1" runat="server">
      </p>
      
      <DIV 
        id="Div1" 
        runat="server" 
        style="DISPLAY: inline; WIDTH: 256px; HEIGHT: 15px" 
        ms_positioning="FlowLayout" />
    </form>
  </body>
</HTML>

<%@ Page Language="VJ#" AutoEventWireup="True" %>
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.JSL.Controls" Assembly="Samples.AspNet.JSL" %>
<HTML>
  <HEAD><title>Custom HtmlInputRadioButton - OnPreRender - VJ# Example</title>
    <script runat="server">
    void Page_Load(Object sender, EventArgs e) 
    {
        Div1.set_InnerHtml("");
    } //Page_Load

    void HtmlInputRadioButtonGroup1_ServerChange(Object sender,
        System.EventArgs e)
    {
        // Diplay the value of the selected HtmlInputRadioButton control.
        System.Web.UI.HtmlControls.HtmlInputRadioButton 
            htmlInputRadioButtonGroup1 = (System.Web.UI.HtmlControls.
            HtmlInputRadioButton)sender;
        Div1.set_InnerHtml("You change your selection to: "
            + htmlInputRadioButtonGroup1.get_Value());
    } //HtmlInputRadioButtonGroup1_ServerChange
    </script>
  </HEAD>
  <body>
    <form id="Form1" method="post" runat="server">
      <h3>Custom HtmlInputRadioButton - OnPreRender - VJ# Example</h3>

      <aspSample:CustomHtmlInputRadioButtonOnPreRender 
        id="HtmlInputRadioButton1" 
        name="HtmlInputRadioButtonGroup1" 
        runat="server" 
        type="radio" checked
        onserverchange="HtmlInputRadioButtonGroup1_ServerChange" 
        value="HtmlInputRadioButton1">HtmlInputRadioButton1
      </aspSample:CustomHtmlInputRadioButtonOnPreRender>
      <br>

      <aspSample:CustomHtmlInputRadioButtonOnPreRender 
        id="HtmlInputRadioButton2" 
        name="HtmlInputRadioButtonGroup1" 
        runat="server" 
        type="radio" 
        onserverchange="HtmlInputRadioButtonGroup1_ServerChange" 
        value="HtmlInputRadioButton2">HtmlInputRadioButton2
      </aspSample:CustomHtmlInputRadioButtonOnPreRender>

      <p>
        <input type="submit" value="Submit" id="Submit1" name="Submit1" runat="server">
      </p>
      
      <DIV 
        id="Div1" 
        runat="server" 
        style="DISPLAY: inline; WIDTH: 256px; HEIGHT: 15px" 
        ms_positioning="FlowLayout" />
    </form>
  </body>
</HTML>

<AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal)> _
Public NotInheritable Class CustomHtmlInputRadioButtonOnPreRender
    Inherits System.Web.UI.HtmlControls.HtmlInputRadioButton

    Protected Overrides Sub OnPreRender(ByVal e As System.EventArgs)

        ' Run the OnPreRender method on the base class.
        MyBase.OnPreRender(e)

        ' Add a Title attribute.
        Me.Attributes.Add("title", "Option " + Me.Value)
    End Sub
End Class

using System.Web;
using System.Security.Permissions;
namespace Samples.AspNet.CS.Controls
{
    [AspNetHostingPermission(SecurityAction.Demand, Level = AspNetHostingPermissionLevel.Minimal)]
    public sealed class CustomHtmlInputRadioButtonOnPreRender : System.Web.UI.HtmlControls.HtmlInputRadioButton
    {
        protected override void OnPreRender(System.EventArgs e)
        {
            // Run the OnPreRender method on the base class.
            base.OnPreRender(e);
            
            // Add a Title attribute.
            this.Attributes.Add("title", "Option " + this.Value);
        }
    }
}

package Samples.AspNet.JSL.Controls;

public class CustomHtmlInputRadioButtonOnPreRender
    extends System.Web.UI.HtmlControls.HtmlInputRadioButton
{
    protected void OnPreRender(System.EventArgs e)
    {
        // Run the OnPreRender method on the base class.
        super.OnPreRender(e);
        // Add a Title attribute.
        this.get_Attributes().Add("title", "Option " + this.get_Value());
    } //OnPreRender
} //CustomHtmlInputRadioButtonOnPreRender

Plattformen

Windows 98, Windows 2000 SP4, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

.NET Framework unterstützt nicht alle Versionen sämtlicher Plattformen. Eine Liste der unterstützten Versionen finden Sie unter Systemanforderungen.

Versionsinformationen

.NET Framework

Unterstützt in: 2.0, 1.1, 1.0

Siehe auch

Referenz

HtmlInputRadioButton-Klasse
HtmlInputRadioButton-Member
System.Web.UI.HtmlControls-Namespace
RegisterRequiresPostBack
PreRender

Weitere Ressourcen

HTML-Serversteuerelemente

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