RequiredFieldValidator.AddAttributesToRender(HtmlTextWriter) Méthode

  • Référence

Définition

Espace de noms:
System.Web.UI.WebControls
Assembly:
System.Web.dll

Ajoute les attributs et les styles HTML qui doivent être rendus pour le contrôle à l'objet HtmlTextWriter spécifié.

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)

Paramètres

writer
HtmlTextWriter

HtmlTextWriter qui représente le flux de sortie utilisé pour restituer le contenu HTML sur le client.

Exemples

L’exemple de code suivant montre comment remplacer la AddAttributesToRender méthode dans un contrôle serveur personnalisé afin que le RequiredFieldValidator message d’erreur s’affiche toujours en gras.

Important

Cet exemple comprend une zone de texte qui accepte une entrée d'utilisateur, ce qui constitue une menace potentielle pour la sécurité. Par défaut, les pages web ASP.NET vérifient que l’entrée d’utilisateur n’inclut pas de script ou d’éléments HTML. Pour plus d’informations, consultez Vue d’ensemble des attaques de script.

<%@ 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 RequiredFieldValidator - AddAttributesToRender - C# Example</title>
    <script runat="server">
      void Button1_Click(Object sender, EventArgs e) 
      {
        if (Page.IsValid) 
        {
          Label1.Text = "Required field is filled!";
        }
        else 
        {
          Label1.Text = "Required field is empty!";
        }
      }
    </script>
  </head>
  <body>
    <form id="Form1" method="post" runat="server">
      <h3>Custom RequiredFieldValidator - AddAttributesToRender - C# 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>

<%@ 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>

using System.Web;
using System.Security.Permissions;

namespace Samples.AspNet.CS.Controls
{
  [AspNetHostingPermission(SecurityAction.Demand, Level=AspNetHostingPermissionLevel.Minimal)]
  public sealed class CustomRequiredFieldValidatorAddAttributesToRender : System.Web.UI.WebControls.RequiredFieldValidator
  {
    protected override void AddAttributesToRender(System.Web.UI.HtmlTextWriter writer)
    {
      // Show the RequiredFieldValidator'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 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

S’applique à