HtmlButton.OnPreRender-Methode

Löst das PreRender-Ereignis aus und registriert das Clientskript für das Generieren des Postbacks.

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 EventArgs, das Ereignisdaten enthält.

Hinweise

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

Beispiel

Im folgenden Codebeispiel wird das Überschreiben der OnPreRender-Methode in einem benutzerdefinierten Serversteuerelement veranschaulicht, sodass diese immer den HtmlButton mit fett formatiertem Text anzeigt.

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.VB.Controls" Assembly="Samples.AspNet.VB" %>
<%@ Page Language="VB" AutoEventWireup="True" %>
<HTML>
  <HEAD>
    <title>Custom HtmlButton - OnPreRender - Visual Basic Example</title>
    <script runat="server">
      Sub Page_Load(sender As Object, e As EventArgs)
        HtmlButton1.Attributes.Add("onclick", "alert('Hello client-side world.');")
      End Sub

      Sub HtmlButton1_ServerClick(sender As Object, e As EventArgs)
        Div1.InnerHtml = "Hello server-side world."
      End Sub
    </script>
  </HEAD>
  <body>
    <form id="Form1" method="post" runat="server">
      <h3>Custom HtmlButton - OnPreRender - Visual Basic Example</h3>

      <aspSample:CustomHtmlButtonOnPreRender
        id="HtmlButton1"
        runat="server"
        type="button"
        onserverclick="HtmlButton1_ServerClick"
        name="HtmlButton1">Button</aspSample:CustomHtmlButtonOnPreRender>&nbsp;&nbsp;

      <DIV id="Div1" runat="server"
        style="DISPLAY: inline; WIDTH: 256px; HEIGHT: 15px"
        ms_positioning="FlowLayout" />
    </form>
  </body>
</HTML>

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS.Controls" Assembly="Samples.AspNet.CS" %>
<%@ Page Language="C#" AutoEventWireup="True" %>
<HTML>
  <HEAD>
    <title>Custom HtmlButton - OnPreRender - C# Example</title>
    <script runat="server">
      void Page_Load(Object sender, EventArgs e)
      {
        HtmlButton1.Attributes.Add("onclick","alert('Hello client-side world.');");
      }

      void HtmlButton1_ServerClick(Object sender, EventArgs e)
      {
        Div1.InnerHtml = "Hello server-side world.";
      }
    </script>
  </HEAD>
  <body>
    <form id="Form1" method="post" runat="server">
      <h3>Custom HtmlButton - OnPreRender - C# Example</h3>

      <aspSample:CustomHtmlButtonOnPreRender
        id="HtmlButton1"
        runat="server"
        type="button"
        onserverclick="HtmlButton1_ServerClick"
        name="HtmlButton1">Html Button</aspSample:CustomHtmlButtonOnPreRender>&nbsp;&nbsp;

      <DIV id="Div1" runat="server"
        style="DISPLAY: inline; WIDTH: 256px; HEIGHT: 15px"
        ms_positioning="FlowLayout" />
    </form>
  </body>
</HTML>

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.JSL.Controls" Assembly="Samples.AspNet.JSL" %>
<%@ Page Language="VJ#" AutoEventWireup="True" %>
<HTML>
  <HEAD>
    <title>Custom HtmlButton - OnPreRender - VJ# Example</title>
    <script runat="server">
 
    void Page_Load(Object sender, EventArgs e)
    {
        HtmlButton1.get_Attributes().Add("onclick",
            "alert('Hello client-side world.');");
    } //Page_Load

    void HtmlButton1_ServerClick(Object sender, EventArgs e)
    {
        Div1.set_InnerHtml("Hello server-side world.");
    } //HtmlButton1_ServerClick
    </script>
  </HEAD>
  <body>
    <form id="Form1" method="post" runat="server">
      <h3>Custom HtmlButton - OnPreRender - VJ# Example</h3>

      <aspSample:CustomHtmlButtonOnPreRender
        id="HtmlButton1"
        runat="server"
        type="button"
        onserverclick="HtmlButton1_ServerClick"
        name="HtmlButton1">Html Button</aspSample:CustomHtmlButtonOnPreRender>&nbsp;&nbsp;

      <DIV id="Div1" runat="server"
        style="DISPLAY: inline; WIDTH: 256px; HEIGHT: 15px"
        ms_positioning="FlowLayout" />
    </form>
  </body>
</HTML>

Imports System.Web
Imports System.Security.Permissions

Namespace Samples.AspNet.VB.Controls

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

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

            ' Call the base class's OnPreRender method.
            MyBase.OnPreRender(e)

            ' Always display the HtmlButton with bold text.
            Me.Style.Add("font-weight", "bold")
        End Sub
    End Class

End Namespace

using System.Web;
using System.Security.Permissions;

namespace Samples.AspNet.CS.Controls
{
    [AspNetHostingPermission(SecurityAction.Demand, Level = AspNetHostingPermissionLevel.Minimal)]
    public sealed class CustomHtmlButtonOnPreRender : System.Web.UI.HtmlControls.HtmlButton
    {
        protected override void OnPreRender(System.EventArgs e)
        {
            // Call the base class's OnPreRender method.
            base.OnPreRender(e);

            // Always display the HtmlButton with bold text.
            this.Style.Add("font-weight", "bold");
        }
    }
}

package Samples.AspNet.JSL.Controls;

public class CustomHtmlButtonOnPreRender
    extends System.Web.UI.HtmlControls.HtmlButton
{
    protected void OnPreRender(System.EventArgs e)
    {
        // Call the base OnPreRender method.
        super.OnPreRender(e);
        // Always display the HtmlButton with bold text.
        this.get_Style().Add("font-weight", "bold");
    } //OnPreRender
} //CustomHtmlButtonOnPreRender

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

HtmlButton-Klasse
HtmlButton-Member
System.Web.UI.HtmlControls-Namespace

Weitere Ressourcen

HTML-Serversteuerelemente

Last updated on 2007-08-20

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