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CustomValidator.AddAttributesToRender(HtmlTextWriter) Metoda

  • Reference

Definice

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

Přidá vlastnosti ovládacího prvku do výstupního datového CustomValidator proudu pro vykreslování v klientovi.

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)

Parametry

writer
HtmlTextWriter

A HtmlTextWriter obsahující výstupní datový proud pro vykreslování v klientovi.

Příklady

Následující příklad kódu ukazuje, jak přepsat metodu AddAttributesToRender ve vlastním ovládacím prvku serveru tak, aby CustomValidator se chybová zpráva vždy zobrazovala tučně.

Důležité

Tento příklad obsahuje textové pole, které přijímá vstup uživatele, což je potenciální bezpečnostní hrozba. Ve výchozím nastavení ASP.NET webových stránek ověřte, že vstup uživatele neobsahuje skript ani prvky HTML. Další informace najdete v tématu Přehled zneužití skriptů.

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet" 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 CustomValidator - AddAttributesToRender - C# Example</title>
    <script runat="server">
    void CustomValidator1_ServerValidate(Object source, ServerValidateEventArgs args) 
    {
      try 
      {
        // Test whether the value entered into the text box is even.
        int i = int.Parse(args.Value);
        args.IsValid = ((i%2) == 0);
      }
      catch(Exception ex)
      {
        args.IsValid = false;
      }
    }
    </script>
  </head>
<body>
  <form id="Form1" method="post" runat="server">
    <h3>Custom CustomValidator - AddAttributesToRender - C# Example</h3>
    
    <asp:Label id="Label1" runat="server" 
    Text="Enter an even number:" AssociatedControlID="TextBox1"/><br />
    
    <asp:TextBox id="TextBox1" runat="server" /> 
    
    <aspSample:CustomCustomValidatorAddAttributesToRender 
      id="Customvalidator1" 
      runat="server" 
      ControlToValidate="TextBox1" 
      Display="Static" 
      ErrorMessage="Not an even number!" 
      OnServerValidate="CustomValidator1_ServerValidate" /><br /><br />
    
    <asp:Button id="Button1" runat="server" Text="Validate" />
    
  </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 CustomValidator - AddAttributesToRender - VB.NET Example</title>
    <script runat="server">
      Sub CustomValidator1_ServerValidate(source As Object, args As ServerValidateEventArgs)
        args.IsValid = False
        Try
          ' Test whether the value entered into the text box is even or not.
          Dim i As Integer = Integer.Parse(args.Value)
          If (i Mod 2) = 0 Then
            args.IsValid = True
          End If
        Catch
        End Try
      End Sub
    </script>
  </head>
<body>
  <form id="Form1" method="post" runat="server">
    <h3>Custom CustomValidator - AddAttributesToRender - VB.NET Example</h3>
    <asp:Label id="Label1" runat="server" Text="Enter an even number:" AssociatedControlID="TextBox1" /><br />
    <asp:TextBox id="TextBox1" runat="server" /> 
    <aspSample:CustomCustomValidatorAddAttributesToRender id="Customvalidator1" runat="server" ControlToValidate="TextBox1" Display="Static" ErrorMessage="Not an even number!" OnServerValidate="CustomValidator1_ServerValidate" /><br /><br />
    <asp:Button id="Button1" runat="server" Text="Validate" />
  </form>
</body>
</html>

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

namespace Samples.AspNet
{
    [AspNetHostingPermission(SecurityAction.Demand, Level = AspNetHostingPermissionLevel.Minimal)]
    public sealed class CustomCustomValidatorAddAttributesToRender : System.Web.UI.WebControls.CustomValidator
    {
        protected override void AddAttributesToRender(System.Web.UI.HtmlTextWriter writer)
        {
        // Show the CompareValidator'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 CustomCustomValidatorAddAttributesToRender
        Inherits System.Web.UI.WebControls.CustomValidator

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

            ' Show the CompareValidator'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

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