To reproduce:

radTreeView1.Filter = "new";
var node = new RadTreeNode( "test" );
radTreeView1.Nodes.Add( node );
//here the node is not in the Nodes collection
if ( radTreeView1.Nodes.Contains( node ) == false )
{
 radTreeView1.Nodes.Add( new RadTreeNode( "test" ) );
}

Workaround: remove the filter, perform the desired check and restore the filter

Say you have a button which clears the old nodes and adds a number of new child nodes to the currently selected node. If the selected node is collapsed, the newly added nodes are not visible but the scrollbar updates as if they were.

Workaround the issue by using the BeginUpdate/EndUpdate methods of RadTreeView when updating the nodes:
radTreeView1.BeginUpdate();
    node.Nodes.Clear();
    foreach (RadTreeNode treeNode in nodes)
    {
        node.Nodes.Add((RadTreeNode)treeNode.Clone());
    }
    radTreeView1.EndUpdate();

To reproduce: private void btnFill_Click(object sender, EventArgs e) { radTreeView.BeginUpdate(); radTreeView.Nodes.Add(new RadTreeNode("root 1")); radTreeView.Nodes.Add(new RadTreeNode("root 2")); radTreeView.Nodes.Add(new RadTreeNode("root 3")); radTreeView.Nodes.Add(new RadTreeNode("root 4")); radTreeView.Nodes[radTreeView.Nodes.Count - 1].Expand(); for (int i = 0; i < 30; i++) { radTreeView.Nodes[radTreeView.Nodes.Count - 1].Nodes.Add(new RadTreeNode("text" +i)); } radTreeView.EndUpdate(); } private void radButton1_Click(object sender, EventArgs e) { radTreeView.BeginUpdate(); foreach (var node in radTreeView.Nodes[radTreeView.Nodes.Count - 1].Nodes.ToArray()) { node.Remove(); } for (int i = 0; i < 99; i++) { radTreeView.Nodes[radTreeView.Nodes.Count - 1].Nodes.Add(new RadTreeNode("aasdasd")); } radTreeView.EndUpdate(); } Workaround - reset the traverser and update the scroll value prior removing the nodes radTreeView.TreeViewElement.Scroller.Traverser.Reset(); 

this.treeView.TreeViewElement.Scroller.UpdateScrollValue();

So is there an event triggered for added nodes when using a datasource?  I want to set the checked state based on a property on the databound item.  Basically this:

I have a treeview set like this in Q1 2012:
            treeViewProjets.DataSource = ViewModel.Projets;
            treeViewProjets.DisplayMember = @"Nom\Nom";
            treeViewProjets.ValueMember = @"Id\Id";
            treeViewProjets.ChildMember = @"Projets\ObjetsProjet";
            treeViewProjets.NodeAdded += new RadTreeView.RadTreeViewEventHandler(treeViewProjets_NodeAdded);
            treeViewProjets.NodeAdding += new RadTreeView.RadTreeViewCancelEventHandler(treeViewProjets_NodeAdding);
            treeViewProjets.NodeFormatting += new TreeNodeFormattingEventHandler(treeViewProjets_NodeFormatting);

I get a root node and many child nodes created, but the events NodeAdded and NodeAdding are never triggered, NodeFormatting triggers fine.

The problem may be reproduced in example application in TreeView/First Look 
The scenario is as follows:
-enter some text as a filter
-delete text - filter should be off
-add new node by context menu -> "New Node" appears twice in the tree view

Improve the drag and drop indicators by giving more clean user friendly design and positioning.

FIX. RadTreeView - SelectedNode and SelectedNodes should be cleared when the DataSource of the control is set to null
test app:
using System;
using System.Data;
using System.Windows.Forms;
using Telerik.WinControls.UI;
namespace Lab.Tree
{
public partial class TreeResetSelectionAfterDataSourceIsSetToNull : MainForm
{
private RadTreeView treeView = new RadTreeView();
public TreeResetSelectionAfterDataSourceIsSetToNull()
{
InitializeComponent();
treeView.Dock = DockStyle.Fill;
treeView.Parent = this;
treeView.BringToFront();
DataTable table = new DataTable();
table.Columns.Add("Id");
table.Columns.Add("Name");
table.Rows.Add("1", "name1");
table.Rows.Add("2", "name2");
table.Rows.Add("3", "name3");
treeView.DisplayMember = "Name";
treeView.DataSource = table;
treeView.MultiSelect = true;
}
protected override void OnButton1Click()
{
Console.WriteLine(treeView.SelectedNodes.Count);
Console.WriteLine(treeView.SelectedNode);
treeView.DataSource = null;
Console.WriteLine("-------------------------------------------");
Console.WriteLine(treeView.SelectedNodes.Count);
Console.WriteLine(treeView.SelectedNode);
}
}
}

To reproduce:
  public Form1()
        {
            InitializeComponent();

            for (int i = 0; i < 10; i++)
            {
                RadTreeNode node = new RadTreeNode("Root node " + i);
                for (int j = 0; j < 10; j++)
         

RadTreeView does not refresh iteself after adding a node on a second level.

FIX. RadTreeView - when adding row in the underlying source, the nodes in the tree are collapsed, even when using DeferRefresh

ADD. RadTreeView - when pressing a letter from the keyboard, the node starting with this letter should be selected.

Resolution: 
Added two new properties: KeyboardSearchEnabled and KeyboardSearchResetInterval. When set the KeyboardSearchEnabled property to true, user can navigate to an item by typing when RadTreeView is focused. 
You can set how long the user must wait before searching with the keyboard is reset using the KeyboardSearchResetInterval property. 

When using TriStateMode with AutoCheckChildNodes, there is no way to determine whether the events are raised by a user action or by programatically checking a node.
view: CheckedMode enumeration for details

To reproduce:

Use the following code on an empty RadTreeView: 

this.TreeView.AddNodeByPath("General\\Billing\\February\\Report.txt");

You will see that the Report.txt node will be added to the Root node

Workaround:

Use the following method:

private RadTreeNodeCollection AddNode(string path)
{
    if (path == String.Empty)
        return this.TreeView.Nodes;


    string node = Path.GetFileName(path);
    RadTreeNodeCollection parent = AddNode(Path.GetDirectoryName(path));


    if (parent.Contains(node))
        return parent[node].Nodes;
    else
        return parent.Add(node).Nodes;
}

Currently we do not support binding to the ToggleState.Indeterminate state automatically because it would require a change in the behavior of the Checked property. If you use the CheckedMember, the ToggleState.Indeterminate state is represent like ToggleState.On. 

Workaround: 
Subscribe to the NodeFormatting and NodeCheckedChanged events: 
void radTreeView1_NodeFormatting(object sender, Telerik.WinControls.UI.TreeNodeFormattingEventArgs e)
{
    Child child = e.Node.DataBoundItem as Child;
    if (child != null)
    {
        e.Node.CheckState = child.Status;
    }
}

void radTreeView1_NodeCheckedChanged(object sender, Telerik.WinControls.UI.TreeNodeCheckedEventArgs e)
{
    Child child = e.Node.DataBoundItem as Child;
    if (child != null)
    {
        child.Status = e.Node.CheckState;
    }
}

To reproduce:

public Form1()
{
    InitializeComponent();
    this.radTreeView1.LazyMode = true; 
    this.radTreeView1.NodesNeeded+=radTreeView1_NodesNeeded;
}

private void radTreeView1_NodesNeeded(object sender, Telerik.WinControls.UI.NodesNeededEventArgs e)
{
    
}

Workaround: set the AllowArbitraryItemHeight property to true.

How to reproduce: 

   public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

       
        private void Form1_Load(object sender, EventArgs e)
        {

            radTreeView1.CheckBoxes = true;
            radTreeView1.TriStateMode = true;

            var rootNode = new RadTreeNode("Root Node");
            
            radTreeView1.Nodes.Add(rootNode);

            // Create two parent nodes
            var parentNode1 = new RadTreeNode("First Parent");
            var parentNode2 = new RadTreeNode("Second Parent");

            // Add the parent nodes to tree view's nodes collection
            rootNode.Nodes.AddRange(parentNode1, parentNode2);
            
            
            // Create a child node
            var radTreeNodes2 = new List<RadTreeNode>
            {
                new RadTreeNode("nA.1"),
                new RadTreeNode("nB.2"),
                new RadTreeNode("nC.3"),
                new RadTreeNode("nD.4"),
                new RadTreeNode("nE.5"),
            };
            
            var radTreeNodes = new List<RadTreeNode>
            {
                new RadTreeNode("nA.1"),
                new RadTreeNode("nB.2"),
                new RadTreeNode("nC.3"),
                new RadTreeNode("nD.4"),
                new RadTreeNode("nE.5"),
            };
            
            // Add the child node to the first parent's nodes collection
            parentNode1.Nodes.AddRange(radTreeNodes);
           
            // Remove the child from the first parent collection and add it to the second parent nodes collection
            //parentNode1.Nodes.Remove(childNode);
            parentNode2.Nodes.AddRange(radTreeNodes2);
            rootNode.ExpandAll();
            rootNode.Checked = true;

        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {
            radTreeView1.Filter = textBox1.Text;

            if(radTreeView1.TopNode != null)
                radTreeView1.TopNode.ExpandAll();
        }
    }

Please refer to the attached sample project. Run the application on a WIndows 10 machine. Switch on the Narrator and try to expand a node then the EnableRadAccessibilityObjects  property is set to true.

Workaround: set the EnableRadAccessibilityObjects property to false.

Hi there 

I found this issue in RadTreeView filtering

I have a 2-level text structure programmatically created

after creation I use the command

radtree.ExpandAll()

This is the only event handled

Private Sub txtFilter_TextChanged(sender As Object, e As EventArgs) Handles txtFilter.TextChanged

        radtreeNavigazione.Filter = txtFilter.Text

End Sub

When I set a filter with at least 4 letters and then I select the text in the filter box and press "back", the app freezes with cpu working at 50 %. 

I use this workaround to solve

Private Sub txtFilter_TextChanged(sender As Object, e As EventArgs) Handles txtFilter.TextChanged

        radtreeNavigazione.Filter = txtFilter.Text

End Sub

I use this workaround

Private Sub txtFilter_TextChanged(sender As Object, e As EventArgs) Handles txtFilter.TextChanged

      radtree.CollapseAll()       

      radtreeNavigazione.Filter = txtFilter.Text

      radtree.ExpandAll()

End Sub

In this way it works, but I wanted to report the issue.

Thank you in advance for your attention