ASP.NET - Click count

To avoid that the clicks made by crawlers and spiders, you can use this simple little trick that filters them out.

We can use a javascript function to call a server side function to add the clicking count.

Use ICallBackEventHandler to process this feature.

• Implementing Client Callbacks Programmatically Without Postbacks in ASP.NET Web Pages
  http://msdn.microsoft.com/en-us/library/ms178208.aspx

    <script type="text/javascript">
        function AddCountToServer(para) {
            CallServer(para);
            window.open("PDF/" + para);
            return false;
        }
    </script>

<asp:TemplateField>
    <ItemTemplate>
        <asp:HyperLink ID="Path" runat="server" NavigateUrl='<%#Eval("id","javascript:return AddCountToServer(\"{0}\");") %>' >Path</asp:HyperLink>
    </ItemTemplate>
</asp:TemplateField>

        public void RaiseCallbackEvent(String eventArgument)
        {
            AddCount(eventArgument);
        }

        public string GetCallbackResult()
        {
            // Returns the results of a callback event to the client.
            return GetCount();
        }

        void Page_Load(object sender, EventArgs e)
        {
            ClientScriptManager cm = Page.ClientScript;
            String cbReference = cm.GetCallbackEventReference(this, "arg",
                "ReceiveServerData", "");
            String callbackScript = "function CallServer(arg, context) {" +
                cbReference + "; }";
            cm.RegisterClientScriptBlock(this.GetType(),
                "CallServer", callbackScript, true);
        }
        
        private AddCount(string para)
        {
            // add count to xml here.
        }

1. Locate the code that starts with public class Global : System.Web.HttpApplication and add the following shaded lines of code:
2. namespace HitCounters
   {
   /// <summary>
   /// Summary description for Global.
   /// </summary>
   public class Global : System.Web.HttpApplication
   {
   

2. The code that writes the counters to the database, makes use of objects like the http://msdn.microsoft.com/library/en-us/cpref/html/frlrfsystemdataoledboledbconnectionclasstopic.asp ⁽⁶⁾, located in http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfsystemdataoledb.asp ⁽⁷⁾ namespace, so you'll need to add a reference to this namespace by adding a using statement, at the top of the page somewhere below the other using statements:

3. The next step is to add code to the Session_Start event. This event will fire once for each user when they request the first page in your Web application, so this place is perfect for your hit counters. Inside this event, the values of the two hit counters are increased; one for the total number of users and one for the current number of users. Once the values are increased, the value of totalNumberOfUsers will be written to the database as well.
   
   Locate the skeleton for the Session_Start event and add the following code:

4. Just as with the Session_Start event, you'll need to write some code for the Session_End event as well. However, instead of increasing the counters, you should decrease the counter for the current number of users only. This means that whenever a user Session times out (usually 20 minutes after they requested their last page), the counter will be decreased, so it accurately holds the number of current users on your site. You should leave the counter for the total number of users untouched.
   Locate the Session_End event, and add this line of code: