แก้ไข

แชร์ผ่าน

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.

protected:
 override void AddAttributesToRender(System::Web::UI::HtmlTextWriter ^ writer);
protected override void AddAttributesToRender (System.Web.UI.HtmlTextWriter writer);
override this.AddAttributesToRender : System.Web.UI.HtmlTextWriter -> unit
Protected Overrides Sub AddAttributesToRender (writer As HtmlTextWriter)

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.

Important

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.

<%@ 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>

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.VB.Controls" Assembly="Samples.AspNet.VB" %>
<%@ Page language="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 CompareValidator - AddAttributesToRender - VB.NET Example</title>
  </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>

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);
        }
    }
}

Imports System.Web
Imports System.Security.Permissions

Namespace Samples.AspNet.VB.Controls
    <AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal)> _
    Public NotInheritable Class CustomCompareValidatorAddAttributesToRender
        Inherits System.Web.UI.WebControls.CompareValidator

        Protected Overrides Sub AddAttributesToRender(ByVal writer As System.Web.UI.HtmlTextWriter)

            ' Show the CompareValidator's error message as bold.
            writer.AddStyleAttribute(System.Web.UI.HtmlTextWriterStyle.FontWeight, "bold")

            ' Call the Base's AddAttributesToRender method.
            MyBase.AddAttributesToRender(writer)
        End Sub
    End Class
End Namespace

Applies to