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HtmlInputText.OnPreRender-Methode

  • Artikel

Löst das PreRender-Ereignis aus.

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 die Ereignisdaten enthält.

Hinweise

Die OnPreRender-Methode wird kurz vor dem Rendern des HtmlInputText-Steuerelements aufgerufen. Die OnPreRender-Methode wird hauptsächlich von Entwicklern von Steuerelementen zum Erweitern der Funktionalität des HtmlInputText-Steuerelements verwendet.

Beispiel

Im folgenden Codebeispiel wird das Überschreiben der OnPreRender-Methode veranschaulicht, sodass diese die MaxLength-Eigenschaft in einem benutzerdefinierten HtmlInputText-Serversteuerelement auf 30 Zeichen festlegt.

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.VB.Controls" Assembly="Samples.AspNet.VB" %>
<%@ Page Language="VB" AutoEventWireup="True" %>

<script runat="server">

  Sub Page_Load(sender As Object, e As EventArgs)

    If Not Page.IsPostBack Then

      HtmlInputText1.Value = "Hello HtmlInputText World."

    End If

  End Sub

  Sub HtmlInputText1_ServerChange(sender As Object, e As System.EventArgs)

    Dim htmlInputText1 As System.Web.UI.HtmlControls.HtmlInputText = CType(sender, System.Web.UI.HtmlControls.HtmlInputText)
    Div1.InnerHtml = "Change the preceding text to:<br>" & htmlInputText1.Value

  End Sub

</script>

<html>
  <head>
    <title>Custom HtmlInputText OnPreRender Example</title>
  </head>

  <body>
    <form id="Form1" method="post" runat="server">

      <h3>Custom HtmlInputText OnPreRender Example</h3>

      <p>Make a change to the text, and then press the ENTER.<br>

      <aspSample:CustomHtmlInputTextOnPreRender 
        id="HtmlInputText1" 
        name="HtmlInputText1" 
        runat="server" 
        type="text"
        size="45"
        style="WIDTH: 305px; HEIGHT: 22px" 
        onserverchange="HtmlInputText1_ServerChange">

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

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS.Controls" Assembly="Samples.AspNet.CS" %>
<%@ Page Language="C#" AutoEventWireup="True" %>

<script runat="server">

  void Page_Load(Object sender, EventArgs e) 
  {
    if (!Page.IsPostBack)
    {
      HtmlInputText1.Value = "Hello HtmlInputText World.";
    }
  }

  void HtmlInputText1_ServerChange(object sender, System.EventArgs e)
  {

    // Diplay the value of the selected HtmlInputText control.
    System.Web.UI.HtmlControls.HtmlInputText htmlInputText1 = (System.Web.UI.HtmlControls.HtmlInputText) sender;
    Div1.InnerHtml = "Change the preceding text to:<br>" + htmlInputText1.Value;

  }

</script>

<html>
  <head>
    <title>Custom HtmlInputText OnPreRender Example</title>
  </head>

  <body>
    
    <form id="Form1" method="post" runat="server">

      <h3>Custom HtmlInputText OnPreRender Example</h3>

      <p>Make a change to the text, and then press the ENTER.<br>

      <aspSample:CustomHtmlInputTextOnPreRender 
        id="HtmlInputText1" 
        name="HtmlInputText1" 
        runat="server" 
        type="text"
        size="45"
        style="WIDTH: 305px; HEIGHT: 22px" 
        onserverchange="HtmlInputText1_ServerChange">

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

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.JSL.Controls" Assembly="Samples.AspNet.JSL" %>
<%@ Page Language="VJ#" AutoEventWireup="True" %>
<HTML>
    <HEAD>
        <title>Custom HtmlInputText - OnPreRender - VJ# Example</title>
    <script runat="server">
    void Page_Load(Object sender, EventArgs e) 
    {
        if (!get_Page().get_IsPostBack()) {
            HtmlInputText1.set_Value("Hello HtmlInputText World.");
        }
    } //Page_Load

    void HtmlInputText1_ServerChange(Object sender, System.EventArgs e)
    {
        // Diplay the value of the selected HtmlInputText control.
        System.Web.UI.HtmlControls.HtmlInputText htmlInputText1 = 
            (System.Web.UI.HtmlControls.HtmlInputText)sender;
        Div1.set_InnerHtml("You change the above text to:<br>" 
            + htmlInputText1.get_Value());
    } //HtmlInputText1_ServerChange
    </script>
    </HEAD>
    <body>
        <form id="Form1" method="post" runat="server">
            <h3>Custom HtmlInputText - OnPreRender - VJ# Example</h3>
      <p>Make a change to the text, then press the Enter key.<br>
        <aspSample:CustomHtmlInputTextOnPreRender 
          id="HtmlInputText1" 
          name="HtmlInputText1" 
          runat="server" 
          type="text"
          size="45"
          style="WIDTH: 305px; HEIGHT: 22px" 
          onserverchange="HtmlInputText1_ServerChange">
      </p>
      <p>
      <DIV 
        id="Div1" 
        runat="server" 
        style="DISPLAY: inline; WIDTH: 256px; HEIGHT: 15px" 
        ms_positioning="FlowLayout" />
      </p>
          
        </form>
    </body>
</HTML>

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

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

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

        ' Set the HtmlInputText object's MaxLength property to 30 characters.
        Me.MaxLength = 30
    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 CustomHtmlInputTextOnPreRender : System.Web.UI.HtmlControls.HtmlInputText
    {
        protected override void OnPreRender(System.EventArgs e)
        {
            // Call the base class's OnPreRender method.
            base.OnPreRender(e);

            // Set the HtmlInputText object's MaxLength property to 30 characters.
            this.MaxLength = 30;
        }
    }
}

package Samples.AspNet.JSL.Controls;

public class CustomHtmlInputTextOnPreRender
    extends System.Web.UI.HtmlControls.HtmlInputText
{
    protected void OnPreRender(System.EventArgs e)
    {
        // Call the base's OnPreRender method.
        super.OnPreRender(e);
        // Set the HtmlInputText's MaxLength to 30 chars.
        this.set_MaxLength(30);
    } //OnPreRender
} //CustomHtmlInputTextOnPreRender

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

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

Weitere Ressourcen

HTML-Serversteuerelemente