I am not accessing the UI Element. I am only removing from the datasource .  Can you give me sample if what i am doing below is not what you are referrring to

Please see the piece of code

Here ParentColl is the datasource. 

       ObservableCollection<TreeElement> ParentColl;

       TreeElement Parent =  ParentColl[1];

       TreeElement ChildItem = Parent.Children.FirstOrDefault();

       Parent.Children.Remove(ChildItem);

Xaml:

<ig:XamDataTree x:Name="MyTree" AllowDrop="True" DisplayMemberPath="Name" ItemsSource="{Binding ParentColl}">
    <ig:XamDataTree.GlobalNodeLayouts>
       <ig:NodeLayout Key="ParentLayout" TargetTypeName="TreeElement" IsDraggable="True" IsDropTarget="True" DisplayMemberPath="Name"/>
    </ig:XamDataTree.GlobalNodeLayouts>
</ig:XamDataTree>

Adding the Class for Parent for your reference:

public class TreeElement

{
     private ObservableCollection<TreeElement> _childNodes;

     public string Name { get; set; }

     public ObservableCollection<TreeElement> Children
    {
        get
         {
             if (this._childNodes == null)
             this._childNodes = new ObservableCollection<TreeElement>();

            return this._childNodes;
         }
    }

}

We've encountered the same issue:

Stack below:

   at Infragistics.Controls.Menus.NodeLayout.UnSubscribeForNotificationsForNodeData(Object nodeData)

   at Infragistics.Controls.Menus.NodesManager.DataManager_CollectionChanged(Object sender, NotifyCollectionChangedEventArgs e)

   at Infragistics.DataManagerBase.OnCollectionChanged(NotifyCollectionChangedEventArgs e)

   at Infragistics.DataManagerBase.OnDataSourceCollectionChanged(NotifyCollectionChangedEventArgs e)

   at Infragistics.DataManager`1.OnDataSourceCollectionChanged(NotifyCollectionChangedEventArgs e)

   at Infragistics.DataManagerBase.<SetDataSource>b__9(DataManagerBase instance, Object s, NotifyCollectionChangedEventArgs e)

   at Infragistics.WeakEventHandler`3.OnEvent(Object source, TEventArgs eventArgs)

   at System.Collections.Specialized.NotifyCollectionChangedEventHandler.Invoke(Object sender, NotifyCollectionChangedEventArgs e)

 It seems, that the latest 2016.2 version has the fix.

Regards

Jarek

Hello,

The fix for issue 221815 was released and is available for versions 15.2.20152.2212, 16.1.20161.2174 and 16.2.20162.2045.

I have verified using those versions and the attached sample project that no NullReferenceException is thrown. Please run the sample and let me know if the behavior is different on your side. If the project does not illustrate your scenario correctly, do not hesitate to modify it and upload it back so I can investigate the behavior further.

Do not hesitate to ask if you have any questions.

Hi,

I used your example with following version '16.1.20161.2056'. I still get the error of null exception. As per your previous post this version should have it resolved, but doesn't seem like it has been resolved for this version. Can you please confirm once again if this version has the issue resolved.

Please ignore previous post. I misread the version in your post. I was testing with version ‘16.1.20161.2056’ and the issue has been resolved for versions ‘15.2.20152.2212’, ‘16.1.20161.2174’ and ‘16.2.20162.2045’. Please confirm if this is correct. I have yet to test with versions that you have stated.

Hello Pranav,

I can confirm that the NullReferenceException when a node is removed is fixed and is not reproducible in versions ‘15.2.20152.2212’, ‘16.1.20161.2174’ and ‘16.2.20162.2045’.

Please let me know if you have any other questions.