RadioButtonList.Render(HtmlTextWriter) 方法
定义
重要
一些信息与预发行产品相关,相应产品在发行之前可能会进行重大修改。 对于此处提供的信息,Microsoft 不作任何明示或暗示的担保。
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 -> unit
Protected 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 始终使用描述性文本显示控件。
<%@ 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类的 RadioButtonList 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该方法,该方法反过来使用RenderItem该方法呈现单个单选按钮列表项。