A better way of forcing data bound WPF ListBox to update?

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I have WPF ListBox which is bound to a ObservableCollection, when the collection changes, all items update their position.

The new position is stored in the collection but the UI does not update. So I added the following:

    void scenarioItems_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
    {
        ToolboxListItem.UpdatePositions();
        lstScenario.ItemsSource = null;
        lstScenario.ItemsSource = ToolboxListItem.ScenarioItems;
        this.lstScenario.SelectedIndex = e.NewStartingIndex;
    }

By setting the ItemsSource to null and then binding it again, the UI is updated,

but this is probably very bad coding :p

Suggestions?

I have a Listbox bound to an object property which is of type List<MyCustomType>() and I verified that the following code updates the listbox when the List is updated.

void On_MyObjProperty_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
{
   MyListBox.Items.Refresh();
}

If you're still facing issues, scan the VS IDE output window (Ctrl+W, O) and see if you can spot any binding errors reported.

EASY way to refresh ListBox in WPF?, How about calling ListBox.UpdateLayout? Of course you also need to update the particular item(s) so that it returns the updated string from the ToString method. A better way of forcing data bound WPF ListBox to update? 1401. How do I update the GUI from another thread? 9. WPF ListBox virtualization screws up displayed items. 59.

WPF binding a list / collection of items to a ListBox, but UI not refreshing after items updated, Solved.

I'm just stupid. While I'd read a lot about using ObservableCollection<> instead of List<>, I just continued to ignore this suggestion and went following other suggestions, to no avail. Got back to my books and reread. It's pretty well explained that ObservableCollection<> is a must use because List<> doesn't provide the INotifyCollectionChange interface needed for the ListBox to update its display when the items change in the collection.

This is the updated code:

private ObservableCollection<StringWrapper> m_AppLog;
ObservableCollection<StringWrapper> Log { get { return m_AppLog; } }

Pretty simple, and doesn't require anything else (e.g. Refresh()). Because ObservableCollection takes care itself of triggering the change event, I was able to remove the unnecessary call:

// notify bound objects
OnPropertyChanged("Log");

ObservableCollection doesn't support an update by a thread which didn't create it. Because my list (a visual log to show the recent errors/info messages) can be updated from different threads, I add to adjust my code this way to ensure the update was done with the list's own dispatcher:

public void AddToLog(string message) {
    if (Thread.CurrentThread != Dispatcher.Thread) {
        // Need for invoke if called from a different thread
        Dispatcher.Invoke(
            DispatcherPriority.Normal, (ThreadStart)delegate() { AddToLog(message); });
    }
    else {
        // add this line at the top of the log
        m_AppLog.Insert(0, new StringWrapper(message));
        // ...

Also note that ObservableCollection<> doesn't support RemoveRange() contrary to List<>. This is part of the possible adjustments required when switching from List to ObservableCollection.

The UpdateSourceTrigger property, Instead, the source was updated only after focus was lost on the TextBox. DataBinding { public partial class DataContextSample : Window { public For those situations where you need more control of the process, this property Introduction to the ListView control � A simple ListView example � ListView, data binding and� The WPF Way. Normally if you were going to data bind a control to your enum you would need to go through a number of steps. First you need to add a XAML namespace for your local enum type and to System in MSCorLib.

I may be having a similar problem to what you are having, but I'm not sure.

I had an ObservableCollection<MyEntity> and a ListBox bound to it. But for some strange reason my ListBox was not being updated when I changed the properties of the MyEntity objects in the list.

After searching for a while I found the following page and I just had to let you know:

http://www.wblum.org/listbind/net3/index.html

It is a very good description of what you have to do to get a ListBox to update when the list, or the objects within it, changes. Hoping you will benefit from this.

ListBox Class (System.Windows.Controls), ListBox controls are often used with data binding. If a property is set by a default style, the property might change from its default value For more information, see Default WPF Themes. Note Gets or sets a path to a value on the source object to serve as the visual Attempts to force capture of the mouse to this element. In my project I have a WPF Listbox bound to an ObservableCollection. Every time I add a new item to the Collection the same item is added to the Listbox automaticly. To display the items in the Listbox I use a XAML Datatemplate. What I want to do is animate an item once when it is added to the Collection/Listbox. Can this be done?

I had the same problem yesterday, and it's a complete piece of crap :) ... I'm not setting mine to null anymore though. In my scenario, I am setting it to MyList.ToArray() (after every time I add to the list).

I've seen multiple "oh, you need to use an ObservableList" <-- complete crap.

I've seen multiple "oh, call 'Refresh'" <-- complete crap.

Please forgive my upsettedness, but I also would expect this to work :)

Data binding in depth, Data binding is a way for your app's UI to display data, and optionally to stay in You could use the one-way mode to bind a ListView to a collection of {x:Bind} is new for Windows 10 and it has better performance. your bindings one-time, and force a manual update at any time with a call to Update. I have a WPF ListBox bound to an ObservableCollection.When things are added to the collection, the ListBox scroll position shifts by the size of the added entries. I'd like to be able to preserve the scroll position, so that even as things are added to the list, the items currently in view don't move.

This is old stuff but, use an ObservableCollection. IF you want the UI to see updates to properties in the Objects of the ObservableCollection you need to implement INotifyPropertyChanged in the class defenition for that object. Then raise the property changed event in the setter of each property.

Public Class Session
Implements INotifyPropertyChanged

Public Event PropertyChanged As PropertyChangedEventHandler _
   Implements INotifyPropertyChanged.PropertyChanged

Private Sub NotifyPropertyChanged(ByVal info As String)
    RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(info))
End Sub

Private _name As String = "No name"
''' <summary>
''' Name of Session
''' </summary>
''' <value></value>
''' <returns></returns>
''' <remarks></remarks>
Public Property Name() As String
    Get
        Return _name
    End Get
    Set(ByVal value As String)
        _name = value
        NotifyPropertyChanged("Name")
    End Set
End Property

Flexible and Powerful Data Binding with WPF, If you are coming from a Windows Forms or ASP.NET background, templates will force you to change the way you think about developing and designing user� WPF binding a list / collection of items to a ListBox, but UI not refreshing after items updated, Solved. I'm just stupid. While I'd read a lot about using ObservableCollection<> instead of List<> , I just continued to ignore this suggestion and went following other suggestions, to no avail.

Wpf ui not updating, One-Way Data Binding Twelve Ways to Improve WPF Performance there are old any more—but there is still a non-zero cost to updating the The DataBinding features provided in WPF 4. How to force WPF property binding to update its source value? WPF ListBox class represents a ListBox control that is a collection of� Tutorial for WP8 - 15-Data Binding w/ Objects & ObservableCollection for Win Phone 8 App Using C# - Duration: 8:11. CCSIT King Faisal University 3,267 views 8:11

How to Databind to a SelectedItems property in WPF, Standard data binding doesn't work, because the SelectedItems I was forced to use my gray-matter and invent a solution of my own. When you set the property , I instantiate another class of my invention, a TwoListSynchronizer. you'll see that the ListBox obediently updates to show all items selected. ItemsControl and its subclasses ListBox and ListView exacerbate performance problems because these controls are highly dynamic (resolution happens “late”), involve WPF collections (which are slow), and have difficult and unpredictable lifetimes for their child controls. Scrollbar performance is often a big problem in larger WPF apps because

Data Binding, clients use two-way data binding, which adds the ability to push information from the As you saw in Chapter 8, data binding in WPF is a much more general tool. To avoid this possibility, you can explicitly force the focus to change before the ListBox, ComboBox, ListView, and DataGrid (and the Menu and TreeView for �

Comments
  • Can you please give more detail on what you mean by "when the collection changes, all items update their position", just so I can be sure I am answering your question properly?
  • This does seem to solve the problem, so I'll move the bug question into another post. Thank you!
  • It's been over two years since someone commented on this... Thank you so much!
  • If the ListBox is binded to a public property "MyItems" and the class with tihs property implements INotifyPropertyChanged, why not just raise the event PropertyChanged(this, "MyItems")? It will notify the UI the this object has changed and update automatically its values.
  • @JoanComasFdz This solution worked for my situation. In my situation the listbox's ItemsSource was databound to an ObservableCollection<BusinessObject>. When BusinessObject.SomeProperty was changed, the list did not reflect that change because BusinessObject was still the same instance (so no notification). The above refresh method caused the list to reevaluate the bindings/converter outputs.
  • I made this mistake also and it took a very long time before I found the solution. +1.
  • this is very great, thanks a lot! Especially that you just need to implement INotifyPropertyChanged for the class contained in the ListBox was interesting for me.
  • This domain is for sale.
  • Trust me, I can understand your frustration, so no offence taken. I have tried using GetBindingExpression but that retuls in a null :p
  • my "GetBindingExpression" doens't return null... but even if I call "UpdateTarget" it does nothing :( ... only in this case... it works great for everything else.
  • Lolz, in my situation, the problem was that someone actually implemented a class called ObservableCollection! So, my collection was not actually implementing INotifyCollectionChanged even though it was called ObservableCollection. Jeez. Once I removed the offending namespace, and used System.Collections.ObjectModel everything was fine. doh!