HtmlInputCheckBox.OnPreRender(EventArgs) Methode

Definitie

Naamruimte:: System.Web.UI.HtmlControls

Assembly:: System.Web.dll

Belangrijk

Bepaalde informatie heeft betrekking op een voorlopige productversie die aanzienlijk kan worden gewijzigd voordat deze wordt uitgebracht. Microsoft biedt geen enkele expliciete of impliciete garanties met betrekking tot de informatie die hier wordt verstrekt.

Hiermee wordt de OnPreRender(EventArgs) gebeurtenis gegenereerd en wordt het besturingselement geregistreerd als een besturingselement waarvoor het afhandelen van terugstortingen is vereist.

protected:
 override void OnPreRender(EventArgs ^ e);

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

protected override void OnPreRender(EventArgs e);

protected internal override void OnPreRender(EventArgs e);

override this.OnPreRender : EventArgs -> unit

Protected Overrides Sub OnPreRender (e As EventArgs)

Protected Friend Overrides Sub OnPreRender (e As EventArgs)

Parameters

e: EventArgs

Een EventArgs met gebeurtenisgegevens.

Voorbeelden

In het volgende codevoorbeeld ziet u hoe u de OnPreRender methode in een aangepast serverbeheer overschrijft, zodat een Title kenmerk aan elk HtmlInputCheckBox besturingselement wordt toegevoegd.

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS.Controls" Assembly="Samples.AspNet.CS" %>
<%@ Page Language="C#" AutoEventWireup="True" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head>
    <title>Custom HtmlInputCheckBox - OnPreRender - C# Example</title>
    <script runat="server">
      void Button1_Click(Object sender, EventArgs e)
      {
        Div1.InnerHtml = "";

        if (HtmlInputCheckBox1.Checked)
        {
          Div1.InnerHtml = "You like basketball. ";
        }

        if (HtmlInputCheckBox2.Checked)
        {
          Div1.InnerHtml += "You like football. ";
        }

        if (HtmlInputCheckBox3.Checked)
        {
          Div1.InnerHtml += "You like soccer. ";
        }
      }
    </script>
  </head>
  <body>
    <form id="Form1" method="post" runat="server">
      <h3>Custom HtmlInputCheckBox - OnPreRender - C# Example</h3>
      <br />
      Enter Interests:<p>
      <aspSample:CustomHtmlInputCheckBoxOnPreRender
        id="HtmlInputCheckBox1"
        runat="server"
        type="checkbox" checked
        value="Basketball"> Basketball

      <aspSample:CustomHtmlInputCheckBoxOnPreRender
        id="HtmlInputCheckBox2"
        runat="server"
        type="checkbox"
        value="Football"> Football

      <aspSample:CustomHtmlInputCheckBoxOnPreRender
        id="HtmlInputCheckBox3"
        runat="server"
        type="checkbox"
        value="Soccer"> Soccer
      </p>
      <p>
      <input id="Button1"
        runat="server"
        type="button"
        value="Enter"
        onserverclick="Button1_Click"
        name="Button1" />
      </p>

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

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.VB.Controls" Assembly="Samples.AspNet.VB" %>
<%@ Page Language="VB" AutoEventWireup="True" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head>
    <title>Custom HtmlInputCheckBox - OnPreRender - Visual Basic Example</title>
    <script runat="server">
      Sub Button1_Click(sender As Object, e As EventArgs)
        Div1.InnerHtml = ""

        If HtmlInputCheckBox1.Checked = True Then
            Div1.InnerHtml = "You like basketball. "
        End If

        If HtmlInputCheckBox2.Checked = True Then
            Div1.InnerHtml += "You like football. "
        End If

        If HtmlInputCheckBox3.Checked = True Then
            Div1.InnerHtml += "You like soccer. "
        End If
      End Sub

    </script>
  </head>
  <body>
    <form id="Form1" method="post" runat="server">
      <h3>Custom HtmlInputCheckBox - OnPreRender - Visual Basic Example</h3>
      <br />
      Enter Interests:<p>
      <aspSample:CustomHtmlInputCheckBoxOnPreRender
        id="HtmlInputCheckBox1"
        runat="server"
        type="checkbox" checked
        value="Basketball"> Basketball

      <aspSample:CustomHtmlInputCheckBoxOnPreRender
        id="HtmlInputCheckBox2"
        runat="server"
        type="checkbox"
        value="Football"> Football

      <aspSample:CustomHtmlInputCheckBoxOnPreRender
        id="HtmlInputCheckBox3"
        runat="server"
        type="checkbox"
        value="Soccer"> Soccer
      </p>
      <p>
      <input id="Button1"
        runat="server"
        type="button"
        value="Enter"
        onserverclick="Button1_Click"
        name="Button1" />
      </p>

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

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

namespace Samples.AspNet.CS.Controls
{
    [AspNetHostingPermission(SecurityAction.Demand, Level = AspNetHostingPermissionLevel.Minimal)]
    public sealed class CustomHtmlInputCheckBoxOnPreRender : System.Web.UI.HtmlControls.HtmlInputCheckBox
    {
        protected override void OnPreRender(System.EventArgs e)
        {
            // Call the base class's OnPreRender method.
            base.OnPreRender(e);
            
            // Add a Title attribute to each HtmlInputCheckBox.
            this.Attributes.Add("title", "If you like " + this.Value + ", then select this check box.");
        }
    }
}

Imports System.Web
Imports System.Security.Permissions

Namespace Samples.AspNet.VB.Controls

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

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

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

            ' Add a Title attribute to each HtmlInputCheckBox.
            Me.Attributes.Add("title", "If you like " + Me.Value + ", then select this check box.")
        End Sub
    End Class

End Namespace

Opmerkingen

De OnPreRender methode overschrijft de basismethode OnPreRender . OnPreRender wordt voornamelijk gebruikt door controleontwikkelaars.

Van toepassing op

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