HtmlSelect.RenderAttributes(HtmlTextWriter) Methode
Definition
Wichtig
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Rendert die Attribute des HtmlSelect-Steuerelements in das angegebene HtmlTextWriter-Objekt.
protected:
override void RenderAttributes(System::Web::UI::HtmlTextWriter ^ writer);protected override void RenderAttributes (System.Web.UI.HtmlTextWriter writer);override this.RenderAttributes : System.Web.UI.HtmlTextWriter -> unitProtected Overrides Sub RenderAttributes (writer As HtmlTextWriter)Parameter
- writer
- HtmlTextWriter
Der HtmlTextWriter, der den gerenderten Inhalt empfängt.
Beispiele
Im folgenden Codebeispiel wird veranschaulicht, wie die RenderAttributes Methode in einem benutzerdefinierten Serversteuerelement überschreiben, sodass für das HtmlSelect Steuerelement immer bestimmte Titeltext angezeigt 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 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>
<br />
<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 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>
<br />
<div id="Div1" runat="server"
style="DISPLAY: inline; WIDTH: 256px; HEIGHT: 15px" />
</form>
</body>
</html>
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);
}
}
}
<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
Hinweise
Die RenderAttributes Methode rendert das name Attribut des HtmlSelect Steuerelements direkt, um sicherzustellen, dass es denselben Wert wie die Control.UniqueID Eigenschaft hat. Nach dem Rendern des Attributs RenderAttributes ruft die RenderAttributes Methode der Basisklasse auf.
Die RenderAttributes Methode wird hauptsächlich von Steuerelemententwicklern verwendet, die die Funktionalität des HtmlSelect Steuerelements erweitern.