RequiredFieldValidator.AddAttributesToRender(HtmlTextWriter) Metod

Definition

Namnområde:
System.Web.UI.WebControls
Sammansättning:
System.Web.dll

Lägger till HTML-attribut och formatmallar som måste återges för kontrollen till det angivna HtmlTextWriter objektet.

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)

Parametrar

writer
HtmlTextWriter

En HtmlTextWriter som representerar utdataströmmen för att återge HTML-innehåll på klienten.

Exempel

Följande kodexempel visar hur du åsidosätter AddAttributesToRender metoden i en anpassad serverkontroll så att RequiredFieldValidator felmeddelandet alltid visas som fetstil.

Important

Det här exemplet har en textruta som accepterar användarindata, vilket är ett potentiellt säkerhetshot. Som standard kontrollerar ASP.NET webbsidor att användarindata inte innehåller skript- eller HTML-element. Mer information finns i Översikt över skriptexploateringar.

<%@ 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 RequiredFieldValidator - AddAttributesToRender - C# Example</title>
    <script runat="server">
      void Button1_Click(Object sender, EventArgs e) 
      {
        if (Page.IsValid) 
        {
          Label1.Text = "Required field is filled!";
        }
        else 
        {
          Label1.Text = "Required field is empty!";
        }
      }
    </script>
  </head>
  <body>
    <form id="Form1" method="post" runat="server">
      <h3>Custom RequiredFieldValidator - AddAttributesToRender - C# Example</h3>

      <table border="0" cellpadding="4" cellspacing="0">
        <tr valign="top">
          <td colspan="3">
            <asp:Label ID="Label1" runat="server" Text="Fill in the required field below" />
          </td>
        </tr>
        <tr>
          <td align="right">Card Number:</td>
          <td>
            <asp:TextBox id="TextBox1" runat="server" />
          </td>
          <td>
            <aspSample:CustomRequiredFieldValidatorAddAttributesToRender 
              id="RequiredFieldValidator1" 
              runat="server" 
              ControlToValidate="TextBox1" 
              Display="Static" 
              ErrorMessage="Required" />
          </td>
        </tr>
        <tr>
          <td> </td>
          <td>
            <asp:Button id="Button1" runat="server" Text="Validate" OnClick="Button1_Click" />
          </td>
          <td> </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 RequiredFieldValidator - AddAttributesToRender - VB.NET Example</title>
        <script runat="server">
            Sub Button1_Click(sender As Object, e As EventArgs) 
            
                If Page.IsValid Then 
                
                    Label1.Text = "Required field is filled!"
                
                Else 
                
                    Label1.Text = "Required field is empty!"
                
                End If

            End Sub
        </script>
    </head>
    <body>
        <form id="Form1" method="post" runat="server">
            <h3>Custom RequiredFieldValidator - AddAttributesToRender - VB.NET Example</h3>

            <table border="0" cellpadding="4" cellspacing="0">
                <tr valign="top">
                    <td colspan="3">
                        <asp:Label ID="Label1" runat="server" 
                         Text="Fill in the required field below" />
                    </td>
                </tr>
                <tr>
                    <td align="right">Card Number:</td>
                    <td>
                        <asp:TextBox id="TextBox1" runat="server" />
                    </td>
                    <td>
                        <aspSample:CustomRequiredFieldValidatorAddAttributesToRender id="RequiredFieldValidator1" 
                         runat="server" ControlToValidate="TextBox1" Display="Static" ErrorMessage="Required" />
                    </td>
                </tr>
                <tr>
                    <td> </td>
                    <td>
                        <asp:Button id="Button1" runat="server" Text="Validate" 
                         OnClick="Button1_Click" />
                    </td>
                    <td> </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 CustomRequiredFieldValidatorAddAttributesToRender : System.Web.UI.WebControls.RequiredFieldValidator
  {
    protected override void AddAttributesToRender(System.Web.UI.HtmlTextWriter writer)
    {
      // Show the RequiredFieldValidator'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 CustomRequiredFieldValidatorAddAttributesToRender
        Inherits System.Web.UI.WebControls.RequiredFieldValidator

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

            ' Show the RequiredFieldValidator'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

Gäller för