RadioButtonList.Render(HtmlTextWriter) 方法
定义
重要
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在客户端上显示 RadioButtonList 控件。
protected:
override void Render(System::Web::UI::HtmlTextWriter ^ writer);protected public:
override void Render(System::Web::UI::HtmlTextWriter ^ writer);protected override void Render (System.Web.UI.HtmlTextWriter writer);protected internal override void Render (System.Web.UI.HtmlTextWriter writer);override this.Render : System.Web.UI.HtmlTextWriter -> unitProtected Overrides Sub Render (writer As HtmlTextWriter)Protected Friend Overrides Sub Render (writer As HtmlTextWriter)参数
- writer
- HtmlTextWriter
包含用于在客户端上进行呈现的输出流的 HtmlTextWriter。
示例
下面的代码示例演示如何重写 Render 自定义服务器控件中的 方法，以便 RadioButtonList 控件始终显示描述性文本。
<%@ Page Language="C#" AutoEventWireup="True" %>
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS.Controls" Assembly="Samples.AspNet.CS" %>
<!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 RadioButtonList - Render - C# Example</title>
</head>
<body>
<form id="Form1" method="post" runat="server">
<h3>Custom RadioButtonList - Render - C# Example</h3>
<aspSample:CustomRadioButtonListRender
id="Radiobuttonlist1"
runat="server"
RepeatColumns="2"
RepeatDirection="Horizontal">
<asp:ListItem Value="Item1">Item1</asp:ListItem>
<asp:ListItem Value="Item2">Item2</asp:ListItem>
<asp:ListItem Value="Item3">Item3</asp:ListItem>
<asp:ListItem Value="Item4">Item4</asp:ListItem>
</aspSample:CustomRadioButtonListRender>
</form>
</body>
</html>
<%@ Page Language="VB" AutoEventWireup="True" %>
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.VB.Controls" Assembly="Samples.AspNet.VB" %>
<!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 RadioButtonList - Render - VB.NET Example</title>
</head>
<body>
<form id="Form1" method="post" runat="server">
<h3>Custom RadioButtonList - Render - VB.NET Example</h3>
<aspSample:CustomRadioButtonListRender
id="Radiobuttonlist1" runat="server"
RepeatColumns="2" RepeatDirection="Horizontal">
<asp:ListItem Value="Item1">Item1</asp:ListItem>
<asp:ListItem Value="Item2">Item2</asp:ListItem>
<asp:ListItem Value="Item3">Item3</asp:ListItem>
<asp:ListItem Value="Item4">Item4</asp:ListItem>
</aspSample:CustomRadioButtonListRender>
</form>
</body>
</html>
using System.Web;
using System.Security.Permissions;
namespace Samples.AspNet.CS.Controls
{
[AspNetHostingPermission(SecurityAction.Demand, Level=AspNetHostingPermissionLevel.Minimal)]
public sealed class CustomRadioButtonListRender : System.Web.UI.WebControls.RadioButtonList
{
protected override void Render(System.Web.UI.HtmlTextWriter writer)
{
// Call the base RenderContents method.
base.Render(writer);
// Append some text to the Image.
writer.Write("Experience Windows Server 2003 and Visual Studio® .NET 2003.");
}
}
}
Imports System.Web
Imports System.Security.Permissions
Namespace Samples.AspNet.VB.Controls
<AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal)> _
Public NotInheritable Class CustomRadioButtonListRender
Inherits System.Web.UI.WebControls.RadioButtonList
Protected Overrides Sub Render(ByVal writer As System.Web.UI.HtmlTextWriter)
' Call the base RenderContents method.
MyBase.Render(writer)
' Append some text to the Image.
writer.Write("Experience Windows Server 2003 and Visual Studio .NET 2003.")
End Sub
End Class
End Namespace
注解
此方法主要由派生自 RadioButtonList 类的自定义控件中的控件开发人员使用。
Render控件的方法实现RadioButtonList初始化RepeatInfo列表的 对象，并调用 RenderRepeater 方法，该方法反过来使用 RenderItem 方法呈现单个单选按钮列表项。
