Live Users

dpkbahuguna · July 15th, 2009, 04:53 AM

hello friend,
I am maiking a little site...in which I am adding a conecpt to see how many users are online for only administrator user. It is working fine If i am running it at my Computer but when I am uploading my site then it is working only 2 or 3 times after that my Application oject gets Null.
I am doing this so to achieve this concept:
--------------------------------------------------------------------------

Global.asax
<%@ Application Language="C#" %>
<%@ Import Namespace="System.Collections.Generic" %>

<script runat="server">
void Application_Start(object sender, EventArgs e)
{
// Code that runs on application startup
List<string> UserOnLine = new List<string>();
Application["UserOnLine"] = UserOnLine;

}
</script>
--------------------------------------------------------------------------
MyLoginPage.aspx
//here as anyone login I am adding it to Application["UserOnline"]

if (PwdChk == Login1.Password)
{
Login1.DestinationPageUrl = "~/UserHome.aspx";
e.Authenticated = true;
//Adding this user to the Live users' list
Application.Lock();
List<string> UserOnLine = new List<string>();
UserOnLine = (List<string>)Application["UserOnLine"];
UserOnLine.Add(Login1.UserName);
Application["UserOnLine"] = UserOnLine;
Application.UnLock();
}
----------------------------------------------------------------------------
Administration.aspx
//here I am showing the online users by clicking the linkbutton.

protected void lnkbt_OnLineUsers_Click(object sender, EventArgs e)
{
try
{
//Listing for Online Users.
List<string> UsersOnline = new List<string>();
UsersOnline = (List<string>)Application["UserOnLine"];
GV_UserOnLine.DataSource = (List<string>)Application["UserOnLine"];
GV_UserOnLine.DataBind();

if (UsersOnline.Count == 0)
lbl_FileContents.Text = "There are no Online user found.";
}
catch (Exception Ex)
{
BLL BLOBJ = new BLL();
BLOBJ.WriteErrorLog(Ex.Message);
Response.Redirect("ServerBusyError.htm");
}

}
=============================================

help me here friends..it is all I am doing to show...

thanks !!!!

dpkbahuguna · July 16th, 2009, 05:34 AM

anyone who cud tell wht is fault in this code

Lee Dumond · July 16th, 2009, 06:09 PM

There are faults with this code.

The main one is that in a hosted situation, the app pool can recycle at any time, and there is no way you can control that. Another is that you are adding users as they log in, but you are doing nothing when users log out. Of course, many users never actually log out, so there's no reliable way to implement that functionality anyway.

Besides, the Membership system already tracks this information, so why reinvent the wheel? This should do the trick nicely.

Code:

protected void btnOnlineUsers_Click(object sender, EventArgs e)
{
   IEnumerable<MembershipUser> users = Membership.GetAllUsers().Cast<MembershipUser>();
   var onlineUsers = users.Where(u => u.IsOnline);
 
   gvUsersOnline.DataSource = onlineUsers;
   gvUsersOnline.DataBind();
}

dpkbahuguna · July 17th, 2009, 01:15 AM

thanks Lee to reply...
IEnumerable<MembershipUser> OLineUsers = Membership.GetAllUsers().Cast<MembershipUser>();
var OLUser = OLineUsers.Where(OLineUsers => OLineUsers.IsOnline);
GV_UserOnLine.DataSource = OLineUsers;
GV_UserOnLine.DataBind();

here I am getting the error in OLineUsers object which I have written in Red Forecolor, I did not get in your code that what is the 'u' object there so I used OlineUsers in place of that... Error is :

Error 2 A local variable named 'OLineUsers' cannot be declared in this scope because it would give a different meaning to 'OLineUsers', which is already used in a 'parent or current' scope to denote something else.

I did not used that object anywhere.

Lee Dumond · July 17th, 2009, 09:08 AM

Yes, this is because OLineUsers is being used in the first line, so you cannot use it in again in the lambda expression.

Also, you are binding the GridView to the wrong collection at the end.

Try this:

Code:

   IEnumerable<MembershipUser> users = Membership.GetAllUsers().Cast<MembershipUser>();
   var onlineUsers = users.Where(u => u.IsOnline);
 
   GV_UserOnline.DataSource = onlineUsers;
   GV_UserOnline.DataBind();

dpkbahuguna · July 18th, 2009, 06:37 AM

thanks lee to reply I used ur code it is running but OnLineUesrs is empty it does not have any user list..one thing I have to ask that how:

IEnumerable<MembershipUser> users = Membership.GetAllUsers().Cast<MembershipUser>();
var onlineUsers = users.Where(u => u.IsOnline);

this all code will get the user list..i mean from where? and as u said before so Application object is not reliable then we cant take any use of Application object when our app pool can recycle any time..? pls make me understnad..