Detect when a session has ended ASP.NET

A problem that I have had in the past is trying to find out when a session has expired within ASP.NET and how to deal with the expired session.   One solution is to add the following code into the Page_Init event.   You can add this event into a class that inherits the Page class so that you can reuse on more than one page or all pages if needed.

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If Not Context.Session Is Nothing Then
If Session.IsNewSession Then
Dim szCookieHeader As String = Request.Headers("Cookie")
If Not String.IsNullOrEmpty(szCookieHeader) And szCookieHeader.IndexOf("ASP.NET_SessionId") >= 0 Then
Response.Redirect("/sessiontimeoutpage.aspx")
End If
End If
End If

This code checks if a new session has been created and if the header has a ASP.NET Session id.   This makes sure that we are checking for a session that has just been created.

Techxplosion.net is live!

A group of us have been working on creating a new tech, geek, gadget site which includes news on the latest trends of all types of technology including mobile devices, smart phones, computers and a whole lot more!   A special thanks to Andy at GT Solutions (www.ghozali.net), Seruni at Madcow Solutions and all the guys who put the effort into making this site great!

Check it out today!

Random number of items from a Generic List extension method

Here is a code snippet  for returning N number of items from a generic list using a extension method.  This requires .NET 3.5.

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public static class Extensions
    {
        /// <summary>
        /// method for returning N number of random items from a generic list
        /// </summary>
        /// <typeparam name="T">Item type</typeparam>
        /// <param name="list">Generic list we wish to retrieve from</param>
        /// <param name="count">number of items to return</param>
        /// <returns></returns>
        public static IEnumerable<T> Randomize<T>(this List<T> list, int count)
        {
            List<T> randomList = new List<T>();
            Random random = new Random();

            while (list.Count > 0)
            {
                //get the next random number between 0 and
                //the list count
                int idx = random.Next(0, list.Count);

                //get that index
                randomList.Add(list[idx]);

                //remove that item so it cant be added again
                list.RemoveAt(idx);
            }

            //return the specified number of items
            return randomList.Take(count);
        }

        /// <summary>
        /// method for returning 1 item from the generic list
        /// </summary>
        /// <typeparam name="T">Item type</typeparam>
        /// <param name="list">Generic list we wish to retrieve from</param>
        /// <param name="count">number of items to return</param>
        /// <returns></returns>
        public static T Randomize<T>(this List<T> list)
        {
            return Randomize(list, 1).FirstOrDefault();
        }
    }

used in code by calling the following: List<mytype> = myGenericList.Randomise(5) or mytype = myGenericList.Randomise();

Could not load file or assembly ‘NameOfAssemblyGoesHere’

Encounted the following error:

Could not load file or assembly ‘NameOfAssemblyGoesHere’ or one of its dependencies. An attempt was made to load a program with an incorrect format.

The problem happened when deploying a web application to a 64bit server where all the required DLL’s where marked as running only on a 32bit system.   You can change this by setting the target platform to AnyCPU which will solve this issue.   There is another workaround which is setting IIS compatability mode to 32bit, Open a command prompt and navigate to the %systemdrive%\Inetpub\AdminScripts directory.  Type in the command cscript.exe adsutil.vbs set W3SVC/AppPools/Enable32BitAppOnWin64 “true”.