HtmlSelect.RenderAttributes-Methode
Rendert die Attribute des HtmlSelect-Steuerelements in das angegebene HtmlTextWriter-Objekt.
Namespace: System.Web.UI.HtmlControls
Assembly: System.Web (in system.web.dll)
Syntax
'Declaration
Protected Overrides Sub RenderAttributes ( _
writer As HtmlTextWriter _
)
'Usage
Dim writer As HtmlTextWriter
Me.RenderAttributes(writer)
protected override void RenderAttributes (
HtmlTextWriter writer
)
protected:
virtual void RenderAttributes (
HtmlTextWriter^ writer
) override
protected void RenderAttributes (
HtmlTextWriter writer
)
protected override function RenderAttributes (
writer : HtmlTextWriter
)
Parameter
- writer
Der HtmlTextWriter, der den gerenderten Inhalt empfängt.
Hinweise
Die RenderAttributes-Methode rendert das name-Attribut des HtmlSelect-Steuerelements direkt, damit dieses genau denselben Wert wie die Control.UniqueID-Eigenschaft hat. Nach dem Rendern des Attributs ruft die RenderAttributes-Methode die RenderAttributes-Methode der Basisklasse auf.
Die RenderAttributes-Methode wird hauptsächlich von Entwicklern von Steuerelementen zum Erweitern der Funktionalität des HtmlSelect-Steuerelements verwendet.
Beispiel
Im folgenden Codebeispiel wird das Überschreiben der RenderAttributes-Methode in einem benutzerdefinierten Serversteuerelement veranschaulicht, sodass im HtmlSelect-Steuerelement immer ein bestimmter Titel angezeigt wird.
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.VB.Controls" Assembly="Samples.AspNet.VB" %>
<%@ Page Language="VB" AutoEventWireup="True" %>
<HTML>
<HEAD>
<title>Custom HtmlSelect - RenderAttributes - VB.NET Example</title>
<script runat="server">
Sub HtmlInputButton1_ServerClick(sender As Object, e As EventArgs)
If HtmlSelect1.SelectedIndex >= 0 Then
If HtmlSelect1.Multiple = True Then
Div1.InnerHtml = "You selected:"
Dim i As Integer
For i = 0 To HtmlSelect1.Items.Count - 1
If HtmlSelect1.Items(i).Selected = True Then
Div1.InnerHtml += "<br> " & HtmlSelect1.Items(i).Value
End If
Next i
Else
Div1.InnerHtml = "You selected " & HtmlSelect1.Value
End If
Else
Div1.InnerHtml = "You did not select an item."
End If
End Sub
</script>
</HEAD>
<body>
<form id="Form1" method="post" runat="server">
<h3>Custom HtmlSelect - RenderAttributes - VB.NET Example</h3>
<p>
<aspSample:CustomHtmlSelectRenderAttributes
id="HtmlSelect1"
name="HtmlSelect1"
runat="server">
<OPTION value="Option1">Option1</OPTION>
<OPTION value="Option2">Option2</OPTION>
<OPTION value="Option3">Option3</OPTION>
</aspSample:CustomHtmlSelectRenderAttributes>
</p>
<p>
<INPUT
id="HtmlInputButton1"
runat="server"
type="button"
onserverclick="HtmlInputButton1_ServerClick"
value="Select"
name="HtmlInputButton1">
</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" %>
<HTML>
<HEAD>
<title>Custom HtmlSelect - RenderAttributes - C# Example</title>
<script runat="server">
void HtmlInputButton1_ServerClick(Object sender, EventArgs e)
{
if (HtmlSelect1.SelectedIndex >= 0)
{
if (HtmlSelect1.Multiple == true)
{
Div1.InnerHtml = "You selected:";
for (int i=0; i<=HtmlSelect1.Items.Count - 1; i++)
{
if (HtmlSelect1.Items[i].Selected == true)
{
Div1.InnerHtml += "<br> " + HtmlSelect1.Items[i].Value;
}
}
}
else
{
Div1.InnerHtml = "You selected " + HtmlSelect1.Value;
}
}
else
{
Div1.InnerHtml = "You did not select an item.";
}
}
</script>
</HEAD>
<body>
<form id="Form1" method="post" runat="server">
<h3>Custom HtmlSelect - RenderAttributes - C# Example</h3>
<p>
<aspSample:CustomHtmlSelectRenderAttributes
id="HtmlSelect1"
name="HtmlSelect1"
runat="server">
<OPTION value="Option1">Option1</OPTION>
<OPTION value="Option2">Option2</OPTION>
<OPTION value="Option3">Option3</OPTION>
</aspSample:CustomHtmlSelectRenderAttributes>
</p>
<p>
<INPUT
id="HtmlInputButton1"
runat="server"
type="button"
onserverclick="HtmlInputButton1_ServerClick"
value="Select"
name="HtmlInputButton1">
</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 HtmlSelect - RenderAttributes - VJ# Example</title>
<script runat="server">
void HtmlInputButton1_ServerClick(Object sender, EventArgs e)
{
if (HtmlSelect1.get_SelectedIndex() >= 0) {
if (HtmlSelect1.get_Multiple() == true) {
Div1.set_InnerHtml("You selected:");
for (int i=0; i<=HtmlSelect1.get_Items().get_Count() - 1; i++) {
if (HtmlSelect1.get_Items().get_Item(i).
get_Selected() == true) {
Div1.set_InnerHtml(Div1.get_InnerHtml()
+ "<br> "
+ HtmlSelect1.get_Items().get_Item(i).get_Value());
}
}
}
else {
Div1.set_InnerHtml("You selected " + HtmlSelect1.get_Value());
}
}
else {
Div1.set_InnerHtml("You did not select an item.");
}
} //HtmlInputButton1_ServerClick
</script>
</HEAD>
<body>
<form id="Form1" method="post" runat="server">
<h3>Custom HtmlSelect - RenderAttributes - VJ# Example</h3>
<p>
<aspSample:CustomHtmlSelectRenderAttributes
id="HtmlSelect1"
name="HtmlSelect1"
runat="server">
<OPTION value="Option1">Option1</OPTION>
<OPTION value="Option2">Option2</OPTION>
<OPTION value="Option3">Option3</OPTION>
</aspSample:CustomHtmlSelectRenderAttributes>
</p>
<p>
<INPUT
id="HtmlInputButton1"
runat="server"
type="button"
onserverclick="HtmlInputButton1_ServerClick"
value="Select"
name="HtmlInputButton1">
</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 CustomHtmlSelectRenderAttributes
Inherits System.Web.UI.HtmlControls.HtmlSelect
Protected Overrides Sub RenderAttributes(ByVal writer As System.Web.UI.HtmlTextWriter)
' Write out Title tag
writer.Write(" Title=""Text from RenderAttributes.""")
' Call the base's RenderAttributes method.
MyBase.RenderAttributes(writer)
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 CustomHtmlSelectRenderAttributes : System.Web.UI.HtmlControls.HtmlSelect
{
protected override void RenderAttributes(System.Web.UI.HtmlTextWriter writer)
{
// Write out Title tag
writer.Write(" Title=\"Text from RenderAttributes.\"");
// Call the base's RenderAttributes method.
base.RenderAttributes(writer);
}
}
}
package Samples.AspNet.JSL.Controls;
public class CustomHtmlSelectRenderAttributes
extends System.Web.UI.HtmlControls.HtmlSelect
{
protected void RenderAttributes(System.Web.UI.HtmlTextWriter writer)
{
// Write out Title tag
writer.Write(" Title=\"Text from RenderAttributes.\"");
// Call the base's RenderAttributes method.
super.RenderAttributes(writer);
} //RenderAttributes
} //CustomHtmlSelectRenderAttributes
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
HtmlSelect-Klasse
HtmlSelect-Member
System.Web.UI.HtmlControls-Namespace
Name
Control.UniqueID
AttributeCollection