Get ListView Visible items

by

Have a look at this question on MSDN showing a technique to find out the visible ListView items –

How to find the rows (ListViewItem(s)) in a ListView that are actually visible?

Here’s the relevant code from that post – 

listView.ItemsSource = from i in Enumerable.Range(0, 100) select "Item" + i.ToString();
listView.Loaded += (sender, e) =>
{
    ScrollViewer scrollViewer = listView.GetVisualChild<ScrollViewer>(); //Extension method
    if (scrollViewer != null)
    {
        ScrollBar scrollBar = scrollViewer.Template.FindName("PART_VerticalScrollBar", scrollViewer) as ScrollBar;
        if (scrollBar != null)
        {
            scrollBar.ValueChanged += delegate
            {
                //VerticalOffset and ViweportHeight is actually what you want if UI virtualization is turned on.
                Console.WriteLine("Visible Item Start Index:{0}", scrollViewer.VerticalOffset);
                Console.WriteLine("Visible Item Count:{0}", scrollViewer.ViewportHeight);
            };
        }
    }
};

Another thing you should do is to use ObservableCollection as your ItemSource instead of an Array; that will definitely improve the performance.

Update:

Ya that might be true(array vs. ObservableCollection) but I would like to see some statistics related to this;

The real benefit of ObservableCollection is if you have a requirement to add/remove items from your ListView at run-time, in case of an Array you will have to reassign the ItemSource of ListView and the ListView first throws away its previous items and regenerates its entire list.

More Related Contents:

  1. Is it possible to implement smooth scroll in a WPF listview?
  2. How do you disable an item in listview control in .net 3.5
  3. Select item programmatically in WPF ListView
  4. How to get ToolTip from WPF Data Grid Column Header (DataGridTemplateColumn) in code?
  5. How to enable assembly bind failure logging (Fusion) in .NET
  6. MVVM: Tutorial from start to finish?
  7. Good or bad practice for Dialogs in wpf with MVVM?
  8. WPF global exception handler [duplicate]
  9. How can I read a file even when getting an “in use by another process” exception?
  10. No output to console from a WPF application?
  11. Change desktop wallpaper using code in .NET
  12. Bring a window to the front in WPF
  13. How to fix a opacity bug with DrawToBitmap on WebBrowser Control?
  14. Bind to SelectedItems from DataGrid or ListBox in MVVM
  15. Make ListView.ScrollIntoView Scroll the Item into the Center of the ListView (C#)
  16. .NET Integer vs Int16?
  17. MVVM in WPF – How to alert ViewModel of changes in Model… or should I?
  18. Passing an enum value as command parameter from XAML
  19. Get the active color of Windows 8 automatic color theme
  20. What are the benefits of resource(.resx) files?
  21. Select either a file or folder from the same dialog in .NET
  22. Sorting an array of folder names like Windows Explorer (Numerically and Alphabetically) – VB.NET
  23. Select folder dialog WPF
  24. How do I create a C# app that decides itself whether to show as a console or windowed app?
  25. Give some command to View in MVVM
  26. How does async works in C#?
  27. Set background color of WPF Textbox in C# code
  28. Error: Must create DependencySource on same Thread as the DependencyObject even by using Dispatcher
  29. How can I wrap text in a label using WPF?
  30. How do I know what monitor a WPF window is in

Leave a Comment