Virtualization Issues

[Deng]

Hi telerk,

I have a table Customers which has 80000 records and my project use a grid to show them(not use Datapager). It can be showed correctly, but it load all data into memory and takes about 150 MB! I heard that RadGridView support data virtualization if its container like grid which have a fixed height.  I make a sample project to verify this,  but it still loaded all data and take amount memory.
How I can do this? Because I can not open the UIVirtulization sample on your WPF samples, Could you send me a sample project for this? Thanks very much
this is  MainWindow code:

<Grid>
       <Grid.RowDefinitions>
           <RowDefinition Height="500"/>
           <RowDefinition Height="50" />
       </Grid.RowDefinitions>
       <telerik:RadGridView ItemsSource="{Binding MyCollection}"  AutoGenerateColumns="False"
                         >
           <telerik:RadGridView.Columns>

               <telerik:GridViewDataColumn Header="CustommerNumber" DataMemberBinding="{Binding CustomerNumber}" IsGroupable="False" IsFilterable="False" />
               <telerik:GridViewDataColumn Header="CompanyName" DataMemberBinding="{Binding CompanyName}" IsSortable="False" />
               <telerik:GridViewDataColumn Header="Address" DataMemberBinding="{Binding Address}" />
               <telerik:GridViewDataColumn Header="PoBox" DataMemberBinding="{Binding POBox}" />
               <telerik:GridViewDataColumn Header="PostalCode" DataMemberBinding="{Binding PostalCode}" />
               <telerik:GridViewDataColumn Header="ContactName" DataMemberBinding="{Binding ContactName}" />
               <telerik:GridViewDataColumn Header="Phone" DataMemberBinding="{Binding Phone}" />
               <telerik:GridViewDataColumn Header="Fax" DataMemberBinding="{Binding Fax}" />
               <telerik:GridViewDataColumn Header="Country" DataMemberBinding="{Binding Country}" />
               <telerik:GridViewDataColumn Header="Mobile" DataMemberBinding="{Binding Mobile}" />
           </telerik:RadGridView.Columns>
       </telerik:RadGridView>
       <ScrollViewer x:Name="LogScrollViewer" VerticalAlignment="Stretch" Grid.Row="1" >
           <!--<Button Click="Button_Click" Content="Load"/>-->
           <TextBox x:Name="tbMemory" Width="200" Height="30"></TextBox>
           <!--<TextBlock x:Name="Log" TextWrapping="Wrap" FontSize="10" />-->
       </ScrollViewer>

   </Grid>

public MainWindow()
       {
           //MessageBox.Show("loading main window");

           InitializeComponent();
           DispatcherTimer timer = new DispatcherTimer();
           timer.Interval = new TimeSpan(0, 0, 1);
           timer.Tick += timer_Tick;
           timer.Start();
           //MessageBox.Show("2");
           this.DataContext = new MyViewModel();

       }

this is MyViewModel code:

class MyViewModel : INotifyPropertyChanged
    {
         #region INotifyPropertyChanged Members

        public event PropertyChangedEventHandler PropertyChanged;

        protected void OnPropertyChanged(string propertyName)
        {

            PropertyChangedEventHandler handler = PropertyChanged;

            if (handler != null)
            {
                handler(this, new PropertyChangedEventArgs(propertyName));
            }
        }

        #endregion

        private RXOfficeEntities context = null;

        private ObservableCollection<Customer> _MyCollection = null;
        public ObservableCollection<Customer> MyCollection
        {
            get { return _MyCollection; }
            set { _MyCollection = value; OnPropertyChanged("MyCollection"); }
        }

        public MyViewModel()
        {
            context = new RXOfficeEntities();
            MyCollection = new ObservableCollection<Customer>(context.Customers);
        }