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ValidationSummary.Render(HtmlTextWriter) Método

  • Referencia

Definición

Espacio de nombres:
System.Web.UI.WebControls
Ensamblado:
System.Web.dll

Envía el contenido del control de servidor al objeto HtmlTextWriter proporcionado, que escribe el contenido que se representará en el cliente.

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

Parámetros

writer
HtmlTextWriter

Flujo de salida que representa el contenido HTML en el cliente.

Ejemplos

En el ejemplo de código siguiente se muestra cómo invalidar el Render método en un control de servidor personalizado para que el ValidationSummary control esté rodeado por una Small etiqueta .

Importante

Este ejemplo tiene un cuadro de texto que acepta datos proporcionados por el usuario, lo que puede suponer una amenaza para la seguridad. De forma predeterminada, ASP.NET Web Pages valida que los datos proporcionados por el usuario no incluyen elementos HTML ni de script. Para más información, consulte Información general sobre los ataques mediante scripts.

<%@ 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 ValidationSummary - Render - C# Example</title>
    </head>
    <body>
        <form id="Form1" method="post" runat="server">
            <h3>Custom ValidationSummary - Render - C# Example</h3>

      <table id="Table1" cellpadding="4" cellspacing="0">
        <tr>
          <td>
            <table id="Table2" cellpadding="4" cellspacing="0" style="background-color:#eeeeee">
              <tr>
                <td colspan="3"><b>Credit Card Information</b> </td>
              </tr>
              <tr>
                <td align="right">Card Type: </td>
                <td>
                  <asp:RadioButtonList id="RadioButtonList1" runat="server" RepeatLayout="Flow">
                      <asp:ListItem>MasterCard</asp:ListItem>
                      <asp:ListItem>Visa</asp:ListItem>
                  </asp:RadioButtonList>
                </td>
                <td align="center" rowspan="1">
                  <asp:RequiredFieldValidator 
                    id="RequiredFieldValidator1" 
                    runat="server" 
                    ErrorMessage="Card Type" 
                    Width="100%" 
                    Display="Static" 
                    ControlToValidate="RadioButtonList1">*
                  </asp:RequiredFieldValidator>
                </td>
              </tr>
              <tr>
                <td align="right">Card Number: </td>
                <td><asp:TextBox id="TextBox1" runat="server"></asp:TextBox></td>
                <td>
                  <asp:RequiredFieldValidator 
                    id="RequiredFieldValidator2" 
                    runat="server" 
                    ErrorMessage="Card Number" 
                    Width="100%" 
                    Display="Static" 
                    ControlToValidate="TextBox1">*
                  </asp:RequiredFieldValidator>
                </td>
              </tr>
              <tr>
                <td></td>
                <td><asp:Button id="Button1" runat="server" text="Validate"></asp:Button></td>
                <td></td>
              </tr>
            </table>
          </td>
        </tr>
        <tr>
          <td valign="top">
            <aspSample:CustomValidationSummaryRender
              id="ValidationSummary1" 
              runat="server" 
              DisplayMode="BulletList" 
              HeaderText="You must enter a value in the following fields:" />
          </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 ValidationSummary - Render - VB.NET Example</title>
    </head>
    <body>
        <form id="Form1" method="post" runat="server">
            <h3>Custom ValidationSummary - Render - VB.NET Example</h3>

            <table id="Table1" cellpadding="4" cellspacing="0">
                <tr>
                    <td>
                        <table id="Table2" cellpadding="4" cellspacing="0" style="background-color:#eeeeee">
                            <tr>
                                <td colspan="3"><b>Credit Card Information</b> </td>
                            </tr>
                            <tr>
                                <td align="right">Card Type: </td>
                                <td><asp:RadioButtonList id="RadioButtonList1" runat="server" RepeatLayout="Flow">
                                        <asp:ListItem>MasterCard</asp:ListItem>
                                        <asp:ListItem>Visa</asp:ListItem>
                                    </asp:RadioButtonList>
                                </td>
                                <td align="center" rowspan="1">
                                    <asp:RequiredFieldValidator id="RequiredFieldValidator1" 
                                        runat="server" ErrorMessage="Card Type" Width="100%" 
                                        Display="Static" ControlToValidate="RadioButtonList1">*</asp:RequiredFieldValidator>
                                </td>
                            </tr>
                            <tr>
                                <td align="right">Card Number: </td>
                                <td><asp:TextBox id="TextBox1" runat="server"></asp:TextBox></td>
                                <td>
                                    <asp:RequiredFieldValidator id="RequiredFieldValidator2" 
                                        runat="server" ErrorMessage="Card Number" Width="100%" 
                                        Display="Static" ControlToValidate="TextBox1">*</asp:RequiredFieldValidator>
                                </td>
                            </tr>
                            <tr>
                                <td></td>
                                <td><asp:Button id="Button1" runat="server" text="Validate"></asp:Button></td>
                                <td></td>
                            </tr>
                        </table>
                    </td>
                </tr>
                <tr>
                    <td valign="top">
                        <aspSample:CustomValidationSummaryRender
                         id="ValidationSummary1" runat="server" DisplayMode="BulletList" 
                         HeaderText="You must enter a value in the following fields:" />
                    </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 CustomValidationSummaryRender : System.Web.UI.WebControls.ValidationSummary
  {
    protected override void Render(System.Web.UI.HtmlTextWriter writer)
    {
      // Write out begining Small HTML tag.
      writer.RenderBeginTag(System.Web.UI.HtmlTextWriterTag.Small);

      // Call the base class's Render method.
      base.Render(writer);

      // Write out ending Small HTML tag.
      writer.RenderEndTag();
    }
  }
}

Imports System.Web
Imports System.Security.Permissions

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

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

            ' Write out begining Small HTML tag.
            writer.RenderBeginTag(System.Web.UI.HtmlTextWriterTag.Small)

            ' Call the base class's Render method.
            MyBase.Render(writer)

            ' Write out ending Small HTML tag.
            writer.RenderEndTag()
        End Sub
    End Class
End Namespace

Se aplica a