In this lesson, you will learn how events can be used in your code, and how to react when those events occur.
Global.asax
![](/Images/OutliningIndicators/ExpandedBlockStart.gif)
<%
@ Application Language="C#" %>
![](/Images/OutliningIndicators/None.gif)
![](/Images/OutliningIndicators/ExpandedBlockStart.gif)
<script runat="server">![](/Images/dot.gif)
![](/Images/OutliningIndicators/InBlock.gif)
void Application_Start(object sender, EventArgs e)
![](/Images/OutliningIndicators/ExpandedSubBlockStart.gif)
{
// 在应用程序启动时运行的代码
Application.Add("userCount", 0);
![](/Images/OutliningIndicators/InBlock.gif)
}
void Application_End(object sender, EventArgs e)
![](/Images/OutliningIndicators/ExpandedSubBlockStart.gif)
{
// 在应用程序关闭时运行的代码
![](/Images/OutliningIndicators/InBlock.gif)
}
void Application_Error(object sender, EventArgs e)
![](/Images/OutliningIndicators/ExpandedSubBlockStart.gif)
{
// 在出现未处理的错误时运行的代码
![](/Images/OutliningIndicators/InBlock.gif)
}
![](/Images/OutliningIndicators/InBlock.gif)
void Session_Start(object sender, EventArgs e)
![](/Images/OutliningIndicators/ExpandedSubBlockStart.gif)
{
// 在新会话启动时运行的代码
int userCount = Int32.Parse(Application.Get("userCount").ToString());
userCount++;
Application.Set("userCount", userCount);
![](/Images/OutliningIndicators/InBlock.gif)
}
![](/Images/OutliningIndicators/InBlock.gif)
void Session_End(object sender, EventArgs e)
![](/Images/OutliningIndicators/ExpandedSubBlockStart.gif)
{
// 在会话结束时运行的代码。
// 注意: 只有在 Web.config 文件中的 sessionstate 模式设置为
// InProc 时,才会引发 Session_End 事件。如果会话模式设置为 StateServer
// 或 SQLServer,则不会引发该事件。
int userCount = Int32.Parse(Application.Get("userCount").ToString());
userCount--;
// Application["userCount"] = userCount;
Application.Set("userCount", userCount);
![](/Images/OutliningIndicators/InBlock.gif)
}
</script>
![](/Images/OutliningIndicators/None.gif)
default.aspx(显示数据)
using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
![](/Images/OutliningIndicators/None.gif)
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
Response.Write("UserCount:" + Application.Get("userCount"));
}
}
![](/Images/OutliningIndicators/None.gif)
但是不知道为什么不会执行Session_End事件.