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CompareValidator.AddAttributesToRender(HtmlTextWriter) Method

  • Reference

Definition

Namespace:
System.Web.UI.WebControls
Assembly:
System.Web.dll

Adds the attributes of this control to the output stream for rendering on the client.

C# 
protected override void AddAttributesToRender(System.Web.UI.HtmlTextWriter writer);

Parameters

writer
HtmlTextWriter

A HtmlTextWriter that contains the output stream for rendering on the client.

Examples

The following code example demonstrates how to override the AddAttributesToRender method in a custom server control so that the CompareValidator error message always appears in bold.

Dôležité

This example has a text box that accepts user input, which is a potential security threat. By default, ASP.NET Web pages validate that user input does not include script or HTML elements. For more information, see Script Exploits Overview.

ASP.NET (C#) 
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS.Controls" Assembly="Samples.AspNet.CS" %>
<%@ Page language="c#" %>
<!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 CompareValidator - AddAttributesToRender - C# Example</title>
    <script runat="server">
      void Page_Load(Object sender, EventArgs e)
      {
        // Run the Page Validate method in order to force
        // the CompareValidate to show it's error message.
        Page.Validate();
      }
    </script>
  </head>
  <body>
    <form id="Form1" method="post" runat="server">
      <h3>Custom CompareValidator - AddAttributesToRender - C# Example</h3>

      <asp:TextBox id="TextBox1" runat="server">123</asp:TextBox><br />

      <asp:TextBox id="TextBox2" runat="server">456</asp:TextBox>

      <aspSample:CustomCompareValidatorAddAttributesToRender
        id="CompareValidator1"
        runat="server"
        ErrorMessage="Value in TextBox2 does not match value in TextBox1."
        Display="Dynamic"
        ControlToCompare="TextBox2"
        ControlToValidate="TextBox1" /><br />

      <asp:Button id="Button1" runat="server" Text="Button" />

    </form>
  </body>
</html>
C# 
using System.Web;
using System.Security.Permissions;

namespace Samples.AspNet.CS.Controls
{
    [AspNetHostingPermission(SecurityAction.Demand, Level = AspNetHostingPermissionLevel.Minimal)]
    public sealed class CustomCompareValidatorAddAttributesToRender : System.Web.UI.WebControls.CompareValidator
    {
        protected override void AddAttributesToRender(System.Web.UI.HtmlTextWriter writer)
        {
        // Show the CompareValidator's error message as bold.
        writer.AddStyleAttribute(System.Web.UI.HtmlTextWriterStyle.FontWeight, "bold");
          
        // Call the Base's AddAttributesToRender method.
        base.AddAttributesToRender(writer);
        }
    }
}

Applies to

Produkt Verzie
.NET Framework 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1