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ValidationSummary.OnPreRender(EventArgs) Metoda

  • Reference

Definice

Obor názvů:
System.Web.UI.WebControls
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

Objekt EventArgs , který obsahuje data události.

Příklady

Následující příklad kódu ukazuje, jak přepsat metodu OnPreRender tak, aby vždy zobrazovala chybové zprávy jako tučné ve vlastním ValidationSummary serverovém ovládacím prvku.

Důležité

Tento příklad obsahuje textové pole, které přijímá vstup uživatele, což je potenciální bezpečnostní hrozba. Ve výchozím nastavení ASP.NET webové stránky ověřují, že uživatelský vstup neobsahuje skript nebo elementy HTML. Další informace najdete v tématu Přehled zneužití skriptů.

<%@ 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

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