RegularExpressionValidator.AddAttributesToRender Method (HtmlTextWriter)

 

Adds to the specified HtmlTextWriter object the HTML attributes and styles that need to be rendered for the control.

Namespace:   System.Web.UI.WebControls
Assembly:  System.Web (in System.Web.dll)

Protected Overrides Sub AddAttributesToRender (
	writer As HtmlTextWriter
)

Parameters

writer
Type: System.Web.UI.HtmlTextWriter

An 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 RegularExpressionValidator error message always displays as bold.

Imports System.Web
Imports System.Security.Permissions

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

        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

The following code example demonstrates how to use the use the CustomRegularExpressionValidatorAddAttributesToRender control, defined in the preceding example, on a Web Forms page.

System_CAPS_security Security Note

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 RegularExpressionValidator - AddAttributesToRender - VB.NET Example</title>
    <script runat="server">
      Sub Button1_Click(sender As Object, e As EventArgs)
          If Page.IsValid Then
              Label1.Text="Page is valid."
          Else
              Label1.Text="Page is not valid!"
          End If
      End Sub
    </script>
    </head>
    <body>
        <form id="Form1" method="post" runat="server">
            <h3>Custom RegularExpressionValidator - AddAttributesToRender - VB.NET Example</h3>
       <table style="background-color:#eeeeee; padding:10">
          <tr valign="top">
             <td colspan="3">
                <asp:Label ID="Label1" 
                  Text="Enter a 5 digit zip code" 
                  runat="server"/>
             </td>
          </tr>

          <tr>
             <td colspan="3">
                <b>Personal Information</b>
             </td>
          </tr>
          <tr>
             <td align="right">
                Zip Code:
             </td>
             <td>
                <asp:TextBox id="TextBox1" runat="server"/>
             </td>
             <td>
                <aspSample:CustomRegularExpressionValidatorAddAttributesToRender 
                  id="Regularexpressionvalidator1" 
                  runat="server"
                  ControlToValidate="TextBox1"
                  ValidationExpression="\d{5}"
                  ErrorMessage="Zip code must be 5 numeric digits"
                  Display="Static"
                  EnableClientScript="False" />
             </td>
          </tr>
          <tr>
             <td></td>
             <td>
                <asp:Button text="Button1" 
                  OnClick="Button1_Click" 
                  runat="server" ID="Button1"/>
             </td>
             <td></td>
          </tr>
       </table>
        </form>
    </body>
</html>

.NET Framework
Available since 1.1
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