How to calculate total no. of user visiting your site.

Step 1: Create a New Project in Visual Studio 2008 as shown in below Figure:

Step 2: Select Asp.net Web Application template from the list of template and name it DemoApplication  as shown below:-

Step 3:- Now we need to add global.asax file. So right Click on your website name from Solution explorer -> Add New Item -> Global Application Class. It will be added in the root directory of your website with the name "Global.asax" as shown in  below two images.

Step 4: First Modify Default.aspx page as below:

Step 5:- Now open global.asax file

•  From the above image we can see that Global class is inheriting from System.web.HttpApplication.
•   It methods, properties, and events that are common to all application objects in an ASP.NET application
•  Now in order to explore more about httpApplication class we are taking example of calculating total No. of User currently accessing a webpage.

Global.asax.cs Code:

protected void Application_Start(object sender, EventArgs e)

        {

            Application["UserCount"] = 0;

        }

        protected void Session_Start(object sender, EventArgs e)

        {

            Application.Lock();//locks access to httpapplicationstate variable to facilitate access synchronization

            Application["UserCount"] = Convert.ToInt32(Application["UserCount"]) + 1;

            Application.UnLock();//release the locks.

        }

        protected void Session_End(object sender, EventArgs e)

        {

            Application.Lock();//locks access to httpapplicationstate variable to facilitate access synchronization

            Application["UserCount"] = Convert.ToInt32(Application["UserCount"]) - 1;

            Application.UnLock();//release the locks

            // Session.Abandon();

        }

Global.asax code Explanation:-

Application_Start:- Here we can place code which runs on application start.Here we have declare Application variable Application[“UserCount”] which is initialized to zero to keep track of user who have currently opened a webpage.

Session_Start:- This method includes code that runs when a new session is started.In this method first we are locking an application object Application[“UserCount”] to facilitate access synchronization and then we are incrementing the variable value which implies that a new user has started a session and then releasing a lock,so that other users session data can be captured.

Session_End:- This method includes code that runs when a session is ended. In this method first we are locking an application object Application[“UserCount”] to facilitate access synchronization and then we are decrementing the variable value to indicate user session has ended and then releasing a lock, so that other users session data can be captured.

Step 6: Now run the application by pressing f5

Step 7:- Now open different browser and copy the url from the first browser and paste it in the new open browser.

By opening a new browser. It is creating a new session for the user on the same machine therefore it is incrementing an application object value.

Note:-We can also set session timeout property in the web.config file to timeout the session after a certain interval of time.