RequiredFieldValidator.AddAttributesToRender(HtmlTextWriter) Methode

Definitie

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

Hiermee worden de HTML-kenmerken en -stijlen toegevoegd die voor het besturingselement moeten worden weergegeven aan het opgegeven HtmlTextWriter object.

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

Een HtmlTextWriter stroom die de uitvoerstroom vertegenwoordigt om HTML-inhoud op de client weer te geven.

Voorbeelden

In het volgende codevoorbeeld ziet u hoe u de AddAttributesToRender methode in een aangepast serverbeheer overschrijft, zodat het RequiredFieldValidator foutbericht altijd vet wordt weergegeven.

Important

Dit voorbeeld heeft een tekstvak dat gebruikersinvoer accepteert. Dit is een mogelijke beveiligingsrisico. Standaard valideren ASP.NET webpagina's dat gebruikersinvoer geen script- of HTML-elementen bevat. Zie Overzicht van Script Exploits voor meer informatie.

<%@ 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

Van toepassing op