ValidationSummary.OnPreRender(EventArgs) 方法
定义
重要
一些信息与预发行产品相关，相应产品在发行之前可能会进行重大修改。 对于此处提供的信息，Microsoft 不作任何明示或暗示的担保。
引发 PreRender 事件。
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 -> unitProtected Overrides Sub OnPreRender (e As EventArgs)Protected Friend Overrides Sub OnPreRender (e As EventArgs)参数
示例
下面的代码示例演示如何重写 方法， OnPreRender 使其始终在自定义 ValidationSummary 服务器控件中以粗体显示错误消息。
重要
此示例具有一个接受用户输入的文本框，这是一个潜在的安全威胁。 默认情况下，ASP.NET 网页验证用户输入是否不包含脚本或 HTML 元素。 有关详细信息，请参阅脚本侵入概述。
<%@ 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
