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ValidationSummary.OnPreRender(EventArgs) Metoda

Definicja

PreRender Zgłasza zdarzenie.

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

Element EventArgs zawierający dane zdarzenia.

Przykłady

Poniższy przykład kodu pokazuje, jak zastąpić metodę OnPreRender tak, aby zawsze wyświetlała komunikaty o błędach jako pogrubione w niestandardowej ValidationSummary kontroli serwera.

Ważne

W tym przykładzie znajduje się pole tekstowe, które akceptuje dane wejściowe użytkownika, co jest potencjalnym zagrożeniem bezpieczeństwa. Domyślnie ASP.NET strony sieci Web weryfikują, czy dane wejściowe użytkownika nie zawierają skryptów ani elementów HTML. Aby uzyskać więcej informacji, zobacz Omówienie luk w zabezpieczeniach skryptów.

<%@ 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 ValidationSummary - AddAttributesToRender - C# Example</title>
    </head>
    <body>
        <form id="Form1" method="post" runat="server">
            <h3>Custom ValidationSummary - AddAttributesToRender - C# Example</h3>

      <table id="Table1" cellpadding="4" cellspacing="0">
        <tr>
          <td>
            <table id="Table2" cellpadding="4" cellspacing="0"
             style="background-color:#eeeeee;">
              <tr>
                <td colspan="3"><b>Credit Card Information</b> </td>
              </tr>
              <tr>
                <td align="right">Card Type: </td>
                <td>
                  <asp:RadioButtonList id="RadioButtonList1" runat="server" RepeatLayout="Flow">
                      <asp:ListItem>MasterCard</asp:ListItem>
                      <asp:ListItem>Visa</asp:ListItem>
                  </asp:RadioButtonList>
                </td>
                <td align="center" rowspan="1">
                  <asp:RequiredFieldValidator 
                    id="RequiredFieldValidator1" 
                    runat="server" 
                    ErrorMessage="Card Type" 
                    Width="100%" 
                    Display="Static" 
                    ControlToValidate="RadioButtonList1">*
                  </asp:RequiredFieldValidator>
                </td>
              </tr>
              <tr>
                <td align="right">Card Number: </td>
                <td><asp:TextBox id="TextBox1" runat="server"></asp:TextBox></td>
                <td>
                  <asp:RequiredFieldValidator 
                    id="RequiredFieldValidator2" 
                    runat="server" 
                    ErrorMessage="Card Number" 
                    Width="100%" 
                    Display="Static" 
                    ControlToValidate="TextBox1">*
                  </asp:RequiredFieldValidator>
                </td>
              </tr>
              <tr>
                <td></td>
                <td><asp:Button id="Button1" runat="server" text="Validate"></asp:Button></td>
                <td></td>
              </tr>
            </table>
          </td>
        </tr>
        <tr>
          <td valign="top">
            <aspSample:CustomValidationSummaryAddAttributesToRender
              id="ValidationSummary1" 
              runat="server" 
              DisplayMode="BulletList" 
              HeaderText="You must enter a value in the following fields:" />
          </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 ValidationSummary - AddAttributesToRender - VB.NET Example</title>
    </head>
    <body>
        <form id="Form1" method="post" runat="server">
            <h3>Custom ValidationSummary - AddAttributesToRender - VB.NET Example</h3>


                <table id="Table1" cellpadding="4" cellspacing="0">
                    <tr>
                        <td>
                            <table id="Table2" cellpadding="4" cellspacing="0" style="background-color:#eeeeee">
                                <tr>
                                    <td colspan="3"><b>Credit Card Information</b> </td>
                                </tr>
                                <tr>
                                    <td align="right">Card Type: </td>
                                    <td><asp:RadioButtonList id="RadioButtonList1" runat="server" RepeatLayout="Flow">
                                            <asp:ListItem>MasterCard</asp:ListItem>
                                            <asp:ListItem>Visa</asp:ListItem>
                                        </asp:RadioButtonList>
                                    </td>
                                    <td align="center" rowspan="1">
                                        <asp:RequiredFieldValidator id="RequiredFieldValidator1" 
                                         runat="server" ErrorMessage="Card Type. " Width="100%" 
                                         Display="Static" ControlToValidate="RadioButtonList1">*</asp:RequiredFieldValidator>
                                    </td>
                                </tr>
                                <tr>
                                    <td align="right">Card Number: </td>
                                    <td><asp:TextBox id="TextBox1" runat="server"></asp:TextBox></td>
                                    <td>
                                        <asp:RequiredFieldValidator id="RequiredFieldValidator2" 
                                         runat="server" ErrorMessage="Card Number. " Width="100%" 
                                         Display="Static" ControlToValidate="TextBox1">*</asp:RequiredFieldValidator>
                                    </td>
                                </tr>
                                <tr>
                                    <td></td>
                                    <td><asp:Button id="Button1" runat="server" text="Validate"></asp:Button></td>
                                    <td></td>
                                </tr>
                            </table>
                        </td>
                        <td valign="top">
                            <table id="Table3" cellpadding="4" cellspacing="0" >
                                <tr>
                                    <td><aspSample:CustomValidationSummaryAddAttributesToRender
                                        id="ValidationSummary1" runat="server" DisplayMode="BulletList"
                                        HeaderText="You must enter a value in the following fields:" />
                                    </td>
                                </tr>
                            </table>
                        </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 CustomValidationSummaryAddAttributesToRender : System.Web.UI.WebControls.ValidationSummary
  {
    protected override void AddAttributesToRender(System.Web.UI.HtmlTextWriter writer)
    {
      // Show the 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 CustomValidationSummaryAddAttributesToRender
        Inherits System.Web.UI.WebControls.ValidationSummary

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

            ' Show the 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

Dotyczy