HtmlInputCheckBox.OnPreRender(EventArgs) Methode
Definition
Wichtig
Einige Informationen beziehen sich auf Vorabversionen, die vor dem Release ggf. grundlegend überarbeitet werden. Microsoft übernimmt hinsichtlich der hier bereitgestellten Informationen keine Gewährleistungen, seien sie ausdrücklich oder konkludent.
Löst das OnPreRender(EventArgs)-Ereignis aus und registriert das -Steuerelement als ein Steuerelement, für das eine Postbackbehandlung erforderlich ist.
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)
Parameter
Beispiele
Im folgenden Codebeispiel wird veranschaulicht, wie die OnPreRender -Methode in einem benutzerdefinierten Serversteuerelement außer Kraft gesetzt wird, sodass jedem HtmlInputCheckBox Steuerelement ein Title
Attribut hinzugefügt wird.
<%@ 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 == true)
{
Div1.InnerHtml = "You like basketball. ";
}
if(HtmlInputCheckBox2.Checked == true)
{
Div1.InnerHtml += "You like football. ";
}
if(HtmlInputCheckBox3.Checked == true)
{
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
Hinweise
Die OnPreRender -Methode überschreibt die Basismethode OnPreRender . OnPreRender wird hauptsächlich von Steuerelemententwicklern verwendet.