HtmlInputHidden.OnPreRender Method (EventArgs)
.NET Framework (current version)
Raises the Control.PreRender event.
Assembly: System.Web (in System.Web.dll)
The OnPreRender method is called just prior to rendering the HtmlInputHidden control. The OnPreRender method is used primarily by control developers extending the functionality of the HtmlInputHidden control.
The following code example demonstrates how to override the OnPreRender method so that it applies HTML encoding to the input value in a custom HtmlInputHidden server control.
<%@ 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>
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); } } }
.NET Framework
Available since 1.1
Available since 1.1
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