RadTreeView SelectedItems collection is not Updated When Items are Removed

Environment

Product	Version
RadTreeView for WPF	2024.2.514

Description

The SelectedItems collection of RadTreeView contains child data items when their associated parent data item is removed from the ItemsSource.

This issue is a limitation coming from the UI virtualization of RadTreeView.

Solution

To resolve this, you will need to manually remove the child items from the SelectedItems collection before removing the parent item.

The exact solution will depend on the exact models strucutre in the application, but the idea is the same. The following example shows how to apply this approach with a very basic model used to populate the TreeView control.

Creating the data model

public class ItemInfo 
{ 
    public string Name { get; set; } 
    public ObservableCollection<ItemInfo> Children { get; set; } 
} 

Populating with data

this.radTreeView.ItemsSource = new ObservableCollection<ItemInfo>() 
{ 
    new ItemInfo()  
    {  
        Name="Item 1",  
        Children = new ObservableCollection<ItemInfo>()  
        { 
             new ItemInfo()  
             {  
                 Name = "Item 1.1", 
                 Children = new ObservableCollection<ItemInfo>() 
                 { 
                     new ItemInfo() { Name = "Item 1.1.1" } 
                 }  
             }  
        } 
    }, 
    new ItemInfo()  
    { 
        Name="Item 2",  
        Children = new ObservableCollection<ItemInfo>()  
        { 
            new ItemInfo() { Name = "Item 2.1" }, 
            new ItemInfo() { Name = "Item 2.2" }, 
            new ItemInfo() { Name = "Item 2.3" }, 
        }  
    }, 
    new ItemInfo() { Name="Item 3" }, 
    new ItemInfo() { Name="Item 4" }, 
}; 

Removing an item along with its children from the ItemsSource

private void RemoveItem(ItemInfo itemToRemove) 
{ 
    DetachChildItemFromSelectedItem(itemToRemove); 
    foreach (var item in this.radTreeView.SelectedItems.ToList()) 
    { 
        RadTreeViewItem container = this.radTreeView.ContainerFromItemRecursive(item); 
        if (container == null) 
        { 
            this.radTreeView.SelectedItems.Remove(item); 
        } 
    } 
 
    var source = (IList)this.radTreeView.ItemsSource; 
    if (source.Count > 0) 
    { 
        source.RemoveAt(0); 
    } 
} 
 
public void DetachChildItemFromSelectedItem(ItemInfo item) 
{ 
    if (item.Children != null && this.radTreeView.SelectedItem != null) 
    { 
        foreach (var property in item.Children) 
        { 
            var childNameHashCode= ((ItemInfo)this.radTreeView.SelectedItem).Name.GetHashCode(); 
            if (property.Name.GetHashCode() == childNameHashCode) 
            { 
                this.radTreeView.SelectedItem = null; 
                return; 
            } 
            DetachChildItemFromSelectedItem(property); 
        } 
    }             
}