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HtmlInputHidden.OnPreRender(EventArgs) Método

  • Referencia

Definición

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

Genera el evento PreRender.

protected:
 override void OnPreRender(EventArgs ^ e);
protected public:
 override void OnPreRender(EventArgs ^ e);
protected override void OnPreRender (EventArgs e);
protected internal override void OnPreRender (EventArgs e);
override this.OnPreRender : EventArgs -> unit
Protected Overrides Sub OnPreRender (e As EventArgs)
Protected Friend Overrides Sub OnPreRender (e As EventArgs)

Parámetros

e
EventArgs

EventArgs que contiene datos de eventos.

Ejemplos

En el ejemplo de código siguiente se muestra cómo invalidar el OnPreRender método para que aplique la codificación HTML al valor de entrada en un control de servidor personalizado HtmlInputHidden .

<%@ 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 HtmlInputHidden - OnPreRender - C# Example</title>
    <script runat="server">
      void Page_Load(Object sender, EventArgs e) 
      {
        HtmlInputHidden1.Value = "<Hello Html Input Hidden World.>";
      }
    </script>
    </head>
    <body onload="alert('View the source to see the HTML Hidden Input value.')">
        <form id="Form1" method="post" runat="server">
            <h3>Custom HtmlInputHidden - OnPreRender - C# Example</h3>
        
          <aspSample:CustomHtmlInputHiddenOnPreRender 
            id="HtmlInputHidden1" 
            name="HtmlInputHidden1"
            runat="server" 
            type="hidden">
            
        </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 HtmlInputHidden - OnPreRender - Visual Basic Example</title>
    
    <script runat="server">
      Sub Page_Load(sender As Object, e As EventArgs)
        HtmlInputHidden1.Value = "<Hello HtmlInputHidden World>"
      End Sub
    </script>
    </head>
    <body onload="alert('View the source to see the HTML Hidden Input value.')">
        <form id="Form1" method="post" runat="server">
            <h3>Custom HtmlInputHidden - OnPreRender - Visual Basic Example</h3>
        
          <aspSample:CustomHtmlInputHiddenOnPreRender 
            id="HtmlInputHidden1" 
            runat="server" 
            type="hidden">
            
        </form>
    </body>
</html>

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

namespace Samples.AspNet.CS.Controls
{
    [AspNetHostingPermission(SecurityAction.Demand, Level = AspNetHostingPermissionLevel.Minimal)]
    public sealed class CustomHtmlInputHiddenOnPreRender : System.Web.UI.HtmlControls.HtmlInputHidden
    {
        protected override void OnPreRender(System.EventArgs e)
        {
            // Call the base class's OnPreRender method.
            base.OnPreRender(e);
            
            // Encode the Hidden Input value as HTML.
            this.Value = System.Web.HttpContext.Current.Server.HtmlEncode(this.Value);
        }
    }
}

<AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal)> _
Public NotInheritable Class CustomHtmlInputHiddenOnPreRender
    Inherits System.Web.UI.HtmlControls.HtmlInputHidden

    Protected Overrides Sub OnPreRender(ByVal e As System.EventArgs)

        ' Call the base class's OnPreRender method.
        MyBase.OnPreRender(e)

        ' Encode the Hidden Input value as HTML.
        Me.Value = System.Web.HttpContext.Current.Server.HtmlEncode(Me.Value)
    End Sub
End Class

Comentarios

Se OnPreRender llama al método justo antes de representar el HtmlInputHidden control. El OnPreRender método se usa principalmente por los desarrolladores de controles que amplían la funcionalidad del HtmlInputHidden control.

Se aplica a

Consulte también