How to see who is online in asp.net website c#

u can use a table "OnlineUsers" to store data of users currently online.

Whenever a user logs in, insert his/her data in this table. In Session_End event in Global.asax file, write a code to remove row of current user.

When a session expires of timeout, it will fire "Session_End" event. When the user logs out, end session programmatically, so this event will be fired.

In this way, u can keep track of currently online users through "OnlineUsers" table.

1. In this page, set a variable LastVisitTime to store the last time the user visiting this page.

2. Use AJAX Timer, and every interval you can update database about the LastVisitTime of this user.

protected void Timer1_Tick(object sender, EventArgs e)
{
  sql.update(update membertable set lastvisittime='" +DateTime.Now+ "' where username='" +User.Name+ "'");

}

3. Set the variable offVisitTime to check if this user is visiting the page.

DateTime lastvisit = Convert.ToDateTime(sql.select("select lastvisittime from membertable where username='" +User.Name+ "'"));
TimeSpan   tSpanDifferent   =DateTime.Now-lastvisit;
If(tSpanDifferent>SpanSpace)//SpanSpace is the variable which is the time span to chech if the user is off-visiting. And you can set it.
//The user is not visiting this page

For example, you can set Timer Interval as 2 minutes and set SpanSpace as 5 minutes.

4. After that, you can get the number of visiting users and who is visiting the page via looping.

[edit] code tags added [/edit]