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ValidationSummary.OnPreRender Method

This API supports the .NET Framework infrastructure and is not intended to be used directly from your code.

Raises the PreRender event.

Namespace:  System.Web.UI.WebControls
Assembly:  System.Web (in System.Web.dll)

protected internal override void OnPreRender(
	EventArgs e
)

Parameters

e
Type: System.EventArgs
An EventArgs that contains the event data.

The following code example demonstrates how to override the OnPreRender method so that it always displays error messages as bold in a custom ValidationSummary server control.

Security noteSecurity Note

This example has a text box that accepts user input, which is a potential security threat. By default, ASP.NET Web pages validate that user input does not include script or HTML elements. For more information, see Script Exploits Overview.


<%@ 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>


...


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);
    }
  }
}


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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