Add a RadTreeView and fill it with nodes so that a vertical scrollbar is shown.

The RadTreeView.TopNode property indicates that it is expected to return the RadTreeNode which visual node element is the first visible one in the current view. But it always return the first data node in RadTreeView no matter which node is currently visible at the top. This is because it consider the RadTreeNode.Visible property. 

Workaround:

            TreeNodeElement neFirstVisible = this.radTreeView1.TreeViewElement.ViewElement.Children[0] as TreeNodeElement;
            RadMessageBox.Show("TopNode = " + neFirstVisible.Data.Text);

Please run the attached sample project and follow the steps illustrated in the gif file. You will notice the following behavior:

If you select multiple items/nodes and then right click on the last selected item/node, the context menu comes up as expected and multiple selection is kept. But if you right click on any other item/node that is selected,the selected nodes become unselected and only the node you are over becomes selected. 

The multiple selection is kept in Windows Explorer and VS Solution explorer wne you right click over an already selected node.

Workaround:

        public RadForm1()
        {
            InitializeComponent();

            this.radTreeView1.MultiSelect = true;
            this.radTreeView1.AllowDefaultContextMenu = true; 
        } 

        class CustomTreeViewElement : RadTreeViewElement
        { 
            protected override Type ThemeEffectiveType
            {
                get
                {
                    return typeof(RadTreeViewElement);
                }
            }

            protected override bool ProcessMouseDown(MouseEventArgs e)
            {
                if (e.Button == MouseButtons.Right)
                {
                    RadContextMenu menu = this.ContextMenu; 
                    RadTreeNode node = this.GetNodeAt(e.Location);
                    if (node!=null)
                    {
                        node.Selected = true;
                    }
                    if (node != null && node.ContextMenu != null)
                    { 
                        menu = node.ContextMenu;
                    } 
                    if (menu == null && this.AllowDefaultContextMenu)
                    {
                        menu = this.InitializeDefaultContextMenu(node);
                    } 
                    if (menu != null)
                    { 
                        RadControl parentControl = (this.ElementTree.Control as RadControl);

                        if (parentControl != null)
                        {
                            menu.ThemeName = parentControl.ThemeName;
                            menu.DropDown.RightToLeft = parentControl.RightToLeft;
                        }

                        TreeViewContextMenuOpeningEventArgs args = new TreeViewContextMenuOpeningEventArgs(node, menu, this);
                        OnContextMenuOpening(args);

                        if (!args.Cancel)
                        {
                            menu.Show(this.ElementTree.Control, e.Location);
                            return true;
                        };
                    }
                }
                return base.ProcessMouseDown(e);
            } 
        }

        class CustomTreeView : RadTreeView
        {  
            protected override RadTreeViewElement CreateTreeViewElement()
            {
                return new CustomTreeViewElement();
            }
           
            public override string ThemeClassName
            {
                get
                {
                    return typeof(RadTreeView).FullName;
                }
            }

            protected override void WndProc(ref Message m)
            {
                switch (m.Msg)
                {
                    case 0x7b:
                         
                        return;
                }

                base.WndProc(ref m);
            }
        }

Greetings,

While testing the exporting feature of RadTreeView, I noticed the following issue :

Using the code below , everything works just fine :

But, the following line of the code raises an error in a specific circumasntance (I describe it more, further in the thread)   :

Error Screenshot is attached : 1.jpg

Details about the error :

The Specific Circumstance :

In my RadTreeView's NodeMouseClick , I add some child nodes to the node which is clicked, at runtime :

Then I found out that setting "exporter.ExportChildNodesGrouped" to True causes the error. But if it is set to false, no error raised even in the above Circumstance.

P.S  Normally setting "exporter.ExportChildNodesGrouped" to True or False doesn't cause any error, but adding some child nodes at run time surly does.

Thanks for your attention.

Add a CodedUI test which records expanding a node in RadTreeView. Run the CodedUI test and you will see that the TestMethod throws the following exception:

"Microsoft.VisualStudio.TestTools.Extension.UITestControlNotFoundException: The playback failed to find the control with given search properties."

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.

Sub New()

        InitializeComponent()
        Me.RadTreeView1.Nodes.Clear()
        Me.RadTreeView1.CheckBoxes = True

        Dim node = New RadTreeNode("1") With {.CheckType = CheckType.CheckBox, .Checked = True, .CheckState = ToggleState.Indeterminate}
        RadTreeView1.Nodes.Add(node)
        node.Nodes.Add(New RadTreeNode("1.1") With {.CheckType = CheckType.RadioButton, .Checked = True, .CheckState = ToggleState.Indeterminate})
        node.Nodes.Add(New RadTreeNode("1.2") With {.CheckType = CheckType.RadioButton})
        node.Nodes.Add(New RadTreeNode("1.3") With {.CheckType = CheckType.RadioButton})
        node = New RadTreeNode("2") With {.CheckType = CheckType.CheckBox, .Checked = True, .CheckState = ToggleState.Indeterminate}
        RadTreeView1.Nodes.Add(node)
        RadTreeView1.Nodes.Add(New RadTreeNode("3"))

    End Sub

Workaround:

    End Sub

I've got a tree with multiple nodes like

document1

 -page 1 

  -page 2

document1

 -page 1 

  -page 2

  -page 3

...

document10

 -page 1 

  -page 2

Due to the size of the treeview, only 2 or 3 documents are on screen, the rest is scrolled. (manually added items, no dynamic or lazy loading)

Lets say I click page 2 of document one, hold the mouse button to select more and go down to the last document (the tree is automatically scrolled down, as expected)

But when I go back to review what I selected, only the last items on screen are selected (documents 9 and 10 for example).

When I try to do the same selection with the arrow keys and the shift key, it works fine, but not with the mouse.

Hello,

I use radbreadcrumb as a group path explorer in my software. 

I associate it with a treeview. Please see the attache photos.

When I select a treeviewitem which has too much parent levels, the radbreadcrumb can not display the path completely.

I've tried autoscrollmargin and autoscrollminsize. No luck. Because my radbreadcrumb is in a splitcontainerpanel, the display size is changeable.

I expect a custom function can act like Windows Explorer (see the last attach photo). When there is no enough display space, only the last levels are shown.

PS. I've integrated the telerik solution from this post. And it works great. 

https://www.telerik.com/forums/getting-breadcrumb-to-act-like-windows-explorer-breadcrumb

Thank you by advance.

Kun

Hi all,

RadTreeView is very nice control , For treeline we can give line style, color but we can't set line thickness,

I want to change thickness of Treeline can you guide me how to do it?

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

Hi All,

I have made User control for custom node, in this user control i have used following controls

1 RadLabel (no of control - 3)

2 RadPanel (no of control -1)

3 PictureBox (no of Control - 4 )

4 TableLayoutPanel (no of control -3)

Means i have used total 11 controls within my user control.

Height of usercontrol = 146

Width of Usercontrol = 595

I have taken RadTreeView and above UserControl added as Node,following properties of treeview is set

this.radTreeView1.DataSource = Staff.GetStaff();
            this.radTreeView1.ParentMember = "ParentID";
            this.radTreeView1.ChildMember = "ID";
            this.radTreeView1.DisplayMember = "Department";
            this.radTreeView1.CreateNodeElement += this.OnCreateNodeElement;

this.radTreeView1.TreeViewElement.AutoSizeItems = true;
            this.radTreeView1.ShowRootLines = false;
            this.radTreeView1.FullRowSelect = false;
            this.radTreeView1.ShowLines = true;
            this.radTreeView1.LineStyle = TreeLineStyle.Solid;
            this.radTreeView1.LineColor = Color.FromArgb(110, 153, 210);
            this.radTreeView1.TreeIndent = 50;

this.radTreeView1.ExpandAll();

But when i run the code it shows like this means my control is not displaying and the property "AutoSizeItems" is not working.

hope for quick reply

Afternoon

We have a RadTReeView that we drag nodes around to reorder within the same treeview.

There are about 2000 nodes in the tree that is a self referencing data bound and goes about 15 levels deep at some parts of the tree

When we click left mouse down (keeping it down) to drag and drop reorder a node, using the mouse wheel to scroll the tree up or down does not work anymore

We want to for instance drag a node from a location to another location outside the current view, using the mouse wheel to navigate the tree view up and down. This used to work, but not after upgrading to the new 2019 telerik.

Is there a tree view control option that needs to be toggled for this to work?

Thank you

Theo

To reproduce:
- Open the Property builder, add some nodes and disable them.
- There is no way to enable them at design time. 

Workaround. 
Disable the nodes at runtime.

To reproduce: add a RadTreeView and a RadBreadCrumb and apply the MaterialTeal theme. Refer to the attached screenshot illustrating the wrong font of the selected item.

Workaround:

    public partial class RadForm1 : Telerik.WinControls.UI.RadForm
    {
        public RadForm1()
        {
            InitializeComponent(); 

            ThemeResolutionService.ApplicationThemeName = "MaterialTeal";

            this.radTreeView1.NodeFormatting += radTreeView1_NodeFormatting;
            this.radTreeView1.SelectedNodeChanged += radTreeView1_SelectedNodeChanged; 
        }
 
        private void UpdateFont()
        {
            foreach (RadSplitButtonElement item in this.radBreadCrumb1.BreadCrumbElement.Items)
            {
                foreach (RadMenuItem menuItem in item.Items)
                {
                    if (this.radTreeView1.SelectedNode != null && menuItem.Text == this.radTreeView1.SelectedNode.Text)
                    {
                        menuItem.Font = new Font(f.FontFamily,f.Size, FontStyle.Bold);
                    }
                }
            }
        }
        
        private void radTreeView1_SelectedNodeChanged(object sender, Telerik.WinControls.UI.RadTreeViewEventArgs e)
        {
            UpdateFont();
        }

        Font f = null;

        private void radTreeView1_NodeFormatting(object sender, Telerik.WinControls.UI.TreeNodeFormattingEventArgs e)
        {
            f = e.NodeElement.ContentElement.Font;
        }

At the moment the filter predicate is called only for the root nodes. A possible workaround is to recursively apply the filter logic for the child nodes as well.
Workaround:
private void Button1_Click(object sender, EventArgs e)
{
    this.radTreeView1.TreeViewElement.FilterPredicate = this.FilterNode;
    this.radTreeView1.Filter = "Custom";
}

private bool FilterNode(RadTreeNode node)
{
    Console.WriteLine(node.Text);
    if (node.Text.Contains("Child: 3"))
    {
        return true;
    }

    Stack<RadTreeNode> children = new Stack<RadTreeNode>();
    if (node.Nodes.Count > 0)
    {
        children.Push(node);
        while (children.Count > 0)
        {
            RadTreeNode current = children.Pop();
            foreach (RadTreeNode child in current.Nodes)
            {
                if (child.Text.Contains("Child: 3"))
                {
                    return true;
                }

                children.Push(child);
            }
        }
    }

    return false;
}

Hi there, through out our app we use the treeview everywhere - but we have had this issue where it crashes when someone right clicks on the treeview where there is no node. This crash happens on the "ContextMenuOpening" event when we try to use e.TreeElement. This is because, on the telerik side of things, the getter for that property is throwing a NullReferenceException (see attached screenshot)

I think this is happening because in your RadTreeViewCancelEventArgs.cs it is this:

        public RadTreeViewElement TreeElement
        {
            get { return node.TreeViewElement; }
        }

        public RadTreeView TreeView
        {
            get { return node.TreeView; }
        }

But since node == null, it throws the exception. It probably should check for null, and if node is null, return a null for those properties - so we can use null conditional operator to check stuff. We have a workaround but it is just lots of copy and paste of things.

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();
        }
    }

To reproduce: please refer to the attached gif files with the different versions of the Telerik UI for WinForms suite . You will notice that while you are dragging a node the default cursor is an arrow with a small rectangle. If you hold the Ctrl key pressed while dragging  the node, the default cursor is an arrow with a small rectangle and '+'. With the latest version, the '+' sign is missing when you hold the Ctrl key. 

To reproduce:
private void RadTreeView1_NodeCheckedChanging(object sender, Telerik.WinControls.UI.RadTreeViewCancelEventArgs e)
{
    Console.WriteLine(e.Action);
}

The action is always unknown.