Sdílet prostřednictvím

HtmlInputHidden.OnPreRender(EventArgs) Metoda

  • Reference

Definice

Obor názvů:
System.Web.UI.HtmlControls
Sestavení:
System.Web.dll

PreRender Vyvolá událost.

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)

Parametry

e
EventArgs

Obsahující EventArgs data události.

Příklady

Následující příklad kódu ukazuje, jak přepsat metodu OnPreRender tak, aby použil kódování HTML na vstupní hodnotu ve vlastním HtmlInputHidden serverovém ovládacím prvku.

<%@ 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

Poznámky

Metoda je OnPreRender volána těsně před vykreslením HtmlInputHidden ovládacího prvku. Metodu OnPreRender primárně používají vývojáři ovládacích HtmlInputHidden prvků, kteří rozšiřují funkce ovládacího prvku.

Platí pro

Viz také