ListView with DataPager problem in .Net 4

I wanted to set the QueryStringField property of the DataPager dynamically. By default, if you do not specify this property, the pager works on a Postback Model.

On the other hand, if you do set the QueryStringField to something, it'll use the value that you set the QueryStringField to as a query string parameter and assign it the appropriate page number (IOW, it makes use of a query string parameter to change the page view)

The declarative and code-behind files are simple enough..

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public partial class _Default : System.Web.UI.Page
{
        public string FieldName
        {
            get
            {
                return "PageID";
            }
        }
        protected override void OnInit(EventArgs e)
        {
            base.OnInit(e);
            ListView1.PagePropertiesChanging += new EventHandler(ListView1_PagePropertiesChanging);
            DataPager1.QueryStringField = FieldName;
        }

        void ListView1_PagePropertiesChanging(object sender, PagePropertiesChangingEventArgs e)
        {
            DataPager1.SetPageProperties(e.StartRowIndex, e.MaximumRows, false);
            BuildAndBind();

        }
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!this.IsPostBack)
            {
                BuildAndBind();
            }

        }
        private void BuildAndBind()
        {
            ListView1.DataSource = BuildDataSource();
            ListView1.DataBind();

        }
        private List BuildDataSource()
        {
            Person a = new Person { FirstName = "A", LastName = "A", Address = "Address1" };
            Person b = new Person { FirstName = "B", LastName = "B", Address = "Address2" };
            Person c = new Person { FirstName = "C", LastName = "C", Address = "Address3" };
            Person d = new Person { FirstName = "D", LastName = "D", Address = "Address4" };
            Person e = new Person { FirstName = "E", LastName = "E", Address = "Address5" };
            Person f = new Person { FirstName = "F", LastName = "F", Address = "Address6" };
            Person g = new Person { FirstName = "G", LastName = "G", Address = "Address7" };
            Person h = new Person { FirstName = "H", LastName = "H", Address = "Address8" };
            Person i = new Person { FirstName = "I", LastName = "I", Address = "Address9" };
            Person j = new Person { FirstName = "J", LastName = "J", Address = "Address10" };
            Person k = new Person { FirstName = "K", LastName = "K", Address = "Address11" };
            Person l = new Person { FirstName = "L", LastName = "L", Address = "Address12" };
            Person m = new Person { FirstName = "M", LastName = "M", Address = "Address13" };


            List list = new List();
            
            list.Add(a);
            list.Add(b);
            list.Add(c);
            list.Add(d);
            list.Add(e);
            list.Add(f);
            list.Add(g);
            list.Add(h);
            list.Add(i);
            list.Add(j);
            list.Add(k);
            list.Add(l);
            list.Add(m);

            return list;
        }
    }

So far...So good..

Using the above example, since we've set the property in the code behind, we'd expect the pager to use a query string to drive the page view. Commenting the line out forces the pager to use a postback model.

What about .Net 4?

the above situations work when the project is set up to run in .NET 3.5 . However, this solution does not seem to work with .NET 4.0 at all. If we set the Target Framework to 4.0, the paging does not work if we want to force a QueryStringField at runtime :(

I've  attached a copy of the vs2010 website here

TestWebApp.zip (2.44 kb)

and the video (in mp4 format...) here

DataPager.mp4 (5.27 mb)

If there's anyone out there who can give me a clue on what's right or wrong, please drop me a few lines.. :)