asp.net 统计显示在线访问人数程序代码

作者：袖梨 2022-06-25

在线用户访问人数，也就是说，要为网站写一个计数器，计数器的初始值为0，网站一开始运行时(Application_Start)，就开始统计，当有用户访问时(Session_Start)计数器加1，当用户访问离开时(Session_End)计数器减1。

在程序开始时，定义一个计数器，初始值为0

代码如下	复制代码
Sub Application_Start(ByVal sender As Object, ByVal e As EventArgs) ' Code that runs on application startup Application("OnlineVisitors") = 0 End SubView Code

当有用户访问网站时:

代码如下	复制代码
Sub Session_Start(ByVal sender As Object, ByVal e As EventArgs) ' Code that runs when a new session is started Application.Lock() Application("OnlineVisitors") = DirectCast(Application("OnlineVisitors"), Integer) + 1 Application.UnLock() End Sub

当用户离开网站时：

代码如下

复制代码

Sub Session_End(ByVal sender As Object, ByVal e As EventArgs)
        ' Code that runs when a session ends.
        ' Note: The Session_End event is raised only when the sessionstate mode
        ' is set to InProc in the Web.config file. If session mode is set to StateServer
        ' or SQLServer, the event is not raised.

        Application.Lock()
        Application("OnlineVisitors") = DirectCast(Application("OnlineVisitors"), Integer) - 1
        Application.UnLock()
    End Sub

上面两个Session_Start和Session_End方法中，Insus.NET有使用Application.Lock和Application.Unlock方法，是为了防止多个线程同时改变这个变量，在变更计数器时，先把它Lock起来，更变完毕，再Unlock。

把Global.asax文件保存，在网页中需要显示网站在线访问人数的位置：