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RenderAttributes Method

HtmlSelect.RenderAttributes Method

Renders the HtmlSelect control's attributes to the specified HtmlTextWriter object.

Namespace: System.Web.UI.HtmlControls
Assembly: System.Web (in system.web.dll)

protected override void RenderAttributes (
	HtmlTextWriter writer
)
protected void RenderAttributes (
	HtmlTextWriter writer
)
protected override function RenderAttributes (
	writer : HtmlTextWriter
)
Not applicable.

Parameters

writer

The HtmlTextWriter that receives the rendered content.

The RenderAttributes method renders the name attribute of the HtmlSelect control directly to ensure that it has the same value as the Control.UniqueID property. After rendering the attribute, the RenderAttributes method calls the base class's RenderAttributes method.

The RenderAttributes method is used primarily by control developers extending the functionality of the HtmlSelect control.

The following code example demonstrates how to override the RenderAttributes method in a custom server control so that specific title text is always displayed for the HtmlSelect control.

<%@ 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 /> &nbsp;&nbsp; " + 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" />&nbsp;&nbsp;
      </p>
      
      <br />
      <div id="Div1" runat="server" 
        style="DISPLAY: inline; WIDTH: 256px; HEIGHT: 15px" />
       
        </form>
    </body>
</html>

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.JSL.Controls" Assembly="Samples.AspNet.JSl" %>
<%@ Page Language="VJ#" 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 - 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 /> &nbsp;&nbsp; " 
                            + 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" />&nbsp;&nbsp;
      </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);
        }
    }
}

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

Windows 98, Windows Server 2000 SP4, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

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