RequiredFieldValidator.AddAttributesToRender Method (HtmlTextWriter)
.NET Framework (current version)
Adds the HTML attributes and styles that need to be rendered for the control to the specified HtmlTextWriter object.
Assembly: System.Web (in System.Web.dll)
Parameters
- writer
-
Type:
System.Web.UI.HtmlTextWriter
A HtmlTextWriter that represents the output stream to render HTML content on the client.
The following code example demonstrates how to override the AddAttributesToRender method in a custom server control so that the RequiredFieldValidator error message always displays as bold.
Security Note
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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.VB.Controls" Assembly="Samples.AspNet.VB" %> <%@ Page Language="VB" 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 RequiredFieldValidator - AddAttributesToRender - VB.NET Example</title> <script runat="server"> Sub Button1_Click(sender As Object, e As EventArgs) If Page.IsValid Then Label1.Text = "Required field is filled!" Else Label1.Text = "Required field is empty!" End If End Sub </script> </head> <body> <form id="Form1" method="post" runat="server"> <h3>Custom RequiredFieldValidator - AddAttributesToRender - VB.NET Example</h3> <table border="0" cellpadding="4" cellspacing="0"> <tr valign="top"> <td colspan="3"> <asp:Label ID="Label1" runat="server" Text="Fill in the required field below" /> </td> </tr> <tr> <td align="right">Card Number:</td> <td> <asp:TextBox id="TextBox1" runat="server" /> </td> <td> <aspSample:CustomRequiredFieldValidatorAddAttributesToRender id="RequiredFieldValidator1" runat="server" ControlToValidate="TextBox1" Display="Static" ErrorMessage="Required" /> </td> </tr> <tr> <td> </td> <td> <asp:Button id="Button1" runat="server" Text="Validate" OnClick="Button1_Click" /> </td> <td> </td> </tr> </table> </form> </body> </html>
Imports System.Web Imports System.Security.Permissions Namespace Samples.AspNet.VB.Controls <AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal)> _ Public NotInheritable Class CustomRequiredFieldValidatorAddAttributesToRender Inherits System.Web.UI.WebControls.RequiredFieldValidator Protected Overrides Sub AddAttributesToRender(ByVal writer As System.Web.UI.HtmlTextWriter) ' Show the RequiredFieldValidator'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
.NET Framework
Available since 1.1
Available since 1.1
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