Calendar.OnPreRender(EventArgs) 方法
定义
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)
参数
示例
下面的代码示例演示如何重写 OnPreRender 方法,以便它始终在自定义服务器控件中显示三个点的边框 Calendar 。The following code example demonstrates how to override the OnPreRender method so that it always displays a three-point border in a custom Calendar server control.
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS.Controls" Assembly="Samples.AspNet.CS" %>
<%@ Page language="c#" %>
<!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 Calendar - OnPreRender - C# Example</title>
</head>
<body>
<form id="Form1" method="post" runat="server">
<h3>Custom Calendar - OnPreRender - C# Example</h3>
<aspSample:CustomCalendarOnPreRender
id="Calendar1"
runat="server" />
</form>
</body>
</html>
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.VB.Controls" Assembly="Samples.AspNet.VB" %>
<%@ Page language="VB" %>
<!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 Calendar - OnPreRender - VB.NET Example</title>
</head>
<body>
<form id="Form1" method="post" runat="server">
<h3>Custom Calendar - OnPreRender - VB.NET Example</h3>
<aspSample:CustomCalendarOnPreRender id="Calendar1" runat="server" />
</form>
</body>
</html>
using System.Web;
using System.Security.Permissions;
namespace Samples.AspNet.CS.Controls
{
[AspNetHostingPermission(SecurityAction.Demand, Level = AspNetHostingPermissionLevel.Minimal)]
public sealed class CustomCalendarOnPreRender : System.Web.UI.WebControls.Calendar
{
protected override void OnPreRender(System.EventArgs e)
{
// Run the OnPreRender method on the base class.
base.OnPreRender(e);
// Display the Calendar with a 3 point border.
this.BorderWidth = System.Web.UI.WebControls.Unit.Point(3);
}
}
}
Imports System.Web
Imports System.Security.Permissions
Namespace Samples.AspNet.VB.Controls
<AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal)> _
Public NotInheritable Class CustomCalendarOnPreRender
Inherits System.Web.UI.WebControls.Calendar
Protected Overrides Sub OnPreRender(ByVal e As System.EventArgs)
' Run the OnPreRender method on the base class.
MyBase.OnPreRender(e)
' Display the Calendar with a 3 point border.
Me.BorderWidth = System.Web.UI.WebControls.Unit.Point(3)
End Sub
End Class
End Namespace
注解
引发事件时,将通过委托调用事件处理程序。Raising an event invokes the event handler through a delegate. 有关详细信息,请参阅 处理和引发事件。For more information, see Handling and Raising Events.
OnPreRender 方法还允许派生类对事件进行处理而不必附加委托。The OnPreRender method also allows derived classes to handle the event without attaching a delegate. 这是在派生类中处理事件的首选技术。This is the preferred technique for handling the event in a derived class.
继承者说明
在派生类中重写 OnPreRender(EventArgs) 时,一定要调用基类的 OnPreRender(EventArgs) 方法,以便已注册的委托对事件进行接收。When overriding OnPreRender(EventArgs) in a derived class, be sure to call the base class's OnPreRender(EventArgs) method so that registered delegates receive the event.