Using a custom control using the Telerik Presentation Framework, I am receiving a NullException inside the GridCheckBoxHeaderCellElement during the GridViewElement's data load.

The custom control construction follows an example I found somewhere (reference is lost to me at this point):

ControlContainingGridView inherits from RadControl

CreateChildItems creates and adds ControlContainingGridViewElement

ControlContainingGridViewElement inherits from RadElement

CreateChildItems creates and adds some layout controls AND a GridViewElement

public partial class ControlContainingGridView : RadControl {
        public ControlContainingGridView() {
            InitializeComponent();
            this.TextChanged += ControlContainingGridView_TextChanged;
        }

        private void ControlContainingGridView_TextChanged(object sender, EventArgs e) {
            controlContainingGridViewElement.Text = this.Text;
        }

        private ControlContainingGridViewElement controlContainingGridViewElement = null;


        protected override void CreateChildItems(RadElement parent) {
            controlContainingGridViewElement = new ControlContainingGridViewElement();
            this.RootElement.Children.Add(controlContainingGridViewElement);
            base.CreateChildItems(parent);
        }

        public object DataSource {
            get {
                return controlContainingGridViewElement.GridView.Template.DataSource;
            }
            set {
                try {
                    controlContainingGridViewElement.GridView.Template.DataSource = value;
                } catch (Exception ex) {
                    Debug.WriteLine(ex);
                }
            }
        }

        internal void SetupColumns(Action<MasterGridViewTemplate> setupColumns) {
            controlContainingGridViewElement.GridView.Template.AutoGenerateColumns = false;
            setupColumns(controlContainingGridViewElement.GridView.Template);
        }



    }

    public class ControlContainingGridViewElement : RadElement {

        private TextPrimitive textPrimitive = null;
        private RadButtonElement addButton = null;
        private RadButtonElement deleteButton = null;
        private RadGridViewElement gridViewElement = null;

        public RadGridViewElement GridView { get { return gridViewElement; } }

        public bool ShowAddButton { get { return addButton.Visibility == ElementVisibility.Visible; } set { addButton.Visibility = value ? ElementVisibility.Visible : ElementVisibility.Collapsed; } }
        public bool ShowDeleteButton { get { return deleteButton.Visibility == ElementVisibility.Visible; } set { deleteButton.Visibility = value ? ElementVisibility.Visible : ElementVisibility.Collapsed; } }

        public string Text { get { return textPrimitive.Text; } set { textPrimitive.Text = value; } }

        protected override void CreateChildElements() {
            DockLayoutPanel dlp = new DockLayoutPanel();
            dlp.StretchHorizontally = true;
            dlp.StretchHorizontally = true;
            dlp.LastChildFill = true;

            DockLayoutPanel dlpBar = new DockLayoutPanel();
            dlpBar.StretchHorizontally = true;
            DockLayoutPanel.SetDock(dlpBar, Dock.Top);


            var imagePrimitive = new ImagePrimitive();
            DockLayoutPanel.SetDock(imagePrimitive, Dock.Left);

            textPrimitive = new TextPrimitive();
            DockLayoutPanel.SetDock(textPrimitive, Dock.Left);

            var slp = new StackLayoutPanel();
            DockLayoutPanel.SetDock(slp, Dock.Right);

            var addButton = new RadButtonElement {
                Text = "Add",
                MaxSize = new Size() { Height = 20 }
            };
            var deleteButton = new RadButtonElement {
                Text = "Del",
                MaxSize = new Size() { Height = 20 }
            };

            slp.Children.Add(addButton);
            slp.Children.Add(deleteButton);


            dlpBar.Children.Add(slp);
            dlpBar.Children.Add(imagePrimitive);
            dlpBar.Children.Add(textPrimitive);



            gridViewElement = new RadGridViewElement {
                StretchHorizontally = true,
                StretchVertically = true
            };
            gridViewElement.Template.AutoSizeColumnsMode = GridViewAutoSizeColumnsMode.Fill;
            gridViewElement.Template.AllowAddNewRow = false;
            gridViewElement.Template.AllowDeleteRow = false;
            gridViewElement.Template.AllowDragToGroup = false;
            gridViewElement.ShowGroupPanel = false;
            gridViewElement.ShowGroupPanelScrollbars = false;

            dlp.Children.Add(dlpBar);
            dlp.Children.Add(gridViewElement);



            this.Children.Add(dlp);
            base.CreateChildElements();
        }

    }

During Form load, I programmatically add columns and provide a binding source

private List<SampleModel> sampleModels = new List<SampleModel>();
        private BindingSource sampleModelsBinding = new BindingSource();

        private void RadForm1_Load(object sender, EventArgs e) {

            sampleModels.Add(new SampleModel() {
                When = DateTime.Parse("1980-04-23"),
                SomeText = "Purple Bananas",
                IsTrue = true
            });
            sampleModels.Add(new SampleModel() {
                When = DateTime.Parse("2002-07-20"),
                SomeText = "Ball & Chain",
                IsTrue = false
            });
            sampleModelsBinding.DataSource = sampleModels;

            controlContainingGridView.SetupColumns((grid) => {
                grid.AddDateTimeColumn(nameof(SampleModel.When), "When");
                grid.AddTextBoxColumn(nameof(SampleModel.SomeText), "Some Text");
                grid.AddCheckBoxColumn(nameof(SampleModel.IsTrue), "Is True");
            });

            controlContainingGridView.DataSource = sampleModelsBinding;

        }

Inclusion of the CheckBox column results in the following error:

Exception thrown: 'System.NullReferenceException' in Telerik.WinControls.GridView.dll

System.NullReferenceException: Object reference not set to an instance of an object.
   at Telerik.WinControls.UI.GridCheckBoxHeaderCellElement.Attach(GridViewColumn data, Object context)
   at Telerik.WinControls.UI.BaseVirtualizedContainer`1.InsertElement(Int32 position, IVirtualizedElement`1 element, T data)
   at Telerik.WinControls.UI.BaseVirtualizedContainer`1.UpdateElement(Int32 position, T data)
   at Telerik.WinControls.UI.BaseVirtualizedContainer`1.MeasureElements()
   at Telerik.WinControls.UI.BaseVirtualizedContainer`1.MeasureOverride(SizeF availableSize)
   at Telerik.WinControls.RadElement.MeasureCore(SizeF availableSize)
   at Telerik.WinControls.RadElement.Measure(SizeF availableSize)
   at Telerik.WinControls.UI.GridVirtualizedRowElement.MeasureElements(SizeF availableSize, SizeF clientSize, Padding borderThickness)
   at Telerik.WinControls.UI.LightVisualElement.MeasureOverride(SizeF availableSize)
   at Telerik.WinControls.UI.GridRowElement.MeasureOverride(SizeF availableSize)
   at Telerik.WinControls.RadElement.MeasureCore(SizeF availableSize)
   at Telerik.WinControls.RadElement.Measure(SizeF availableSize)
   at Telerik.WinControls.UI.VirtualizedStackContainer`1.MeasureElementCore(RadElement element, SizeF availableSize)
   at Telerik.WinControls.UI.ScrollableRowsContainerElement.MeasureElementCore(RadElement element, SizeF availableSize)
   at Telerik.WinControls.UI.VirtualizedStackContainer`1.MeasureElement(IVirtualizedElement`1 element)
   at Telerik.WinControls.UI.PinnedRowsContainerElement.MeasureElement(IVirtualizedElement`1 element)
   at Telerik.WinControls.UI.BaseVirtualizedContainer`1.MeasureElements()
   at Telerik.WinControls.UI.BaseVirtualizedContainer`1.MeasureOverride(SizeF availableSize)
   at Telerik.WinControls.UI.ScrollableRowsContainerElement.MeasureOverride(SizeF availableSize)
   at Telerik.WinControls.RadElement.MeasureCore(SizeF availableSize)
   at Telerik.WinControls.RadElement.Measure(SizeF availableSize)
   at Telerik.WinControls.UI.RowsContainerElement.MeasureOverride(SizeF availableSize)
   at Telerik.WinControls.RadElement.MeasureCore(SizeF availableSize)
   at Telerik.WinControls.RadElement.Measure(SizeF availableSize)
   at Telerik.WinControls.UI.ScrollViewElement`1.MeasureViewElement(SizeF availableSize)
   at Telerik.WinControls.UI.ScrollViewElement`1.MeasureView(SizeF availableSize)
   at Telerik.WinControls.UI.ScrollViewElement`1.MeasureOverride(SizeF availableSize)
   at Telerik.WinControls.UI.GridTableElement.MeasureOverride(SizeF availableSize)
   at Telerik.WinControls.RadElement.MeasureCore(SizeF availableSize)
   at Telerik.WinControls.RadElement.Measure(SizeF availableSize)
   at Telerik.WinControls.Layouts.DockLayoutPanel.MeasureOverride(SizeF constraint)
   at Telerik.WinControls.RadElement.MeasureCore(SizeF availableSize)
   at Telerik.WinControls.RadElement.Measure(SizeF availableSize)
   at Telerik.WinControls.Layouts.ContextLayoutManager.UpdateLayout()
   at Telerik.WinControls.UI.GridVisibilityHelper.EnsureRowVisible(GridViewRowInfo rowInfo)
   at Telerik.WinControls.UI.GridTableElement.EnsureRowVisible(GridViewRowInfo rowInfo)
   at Telerik.WinControls.UI.GridTableElement.EnsureCellVisible(GridViewRowInfo rowInfo, GridViewColumn column)
   at Telerik.WinControls.UI.GridTableElement.UpdateViewCore(Object sender, DataViewChangedEventArgs args)
   at Telerik.WinControls.UI.GridTableElement.UpdateView(Object sender, DataViewChangedEventArgs args)
   at Telerik.WinControls.UI.GridTableElement.ProcessTemplateEvent(GridViewEvent eventData)
   at Telerik.WinControls.UI.GridTableElement.Telerik.WinControls.UI.IGridViewEventListener.ProcessEvent(GridViewEvent eventData)
   at Telerik.WinControls.UI.GridViewEventProcessEntity.ProcessCollection(GridViewEvent gridEvent, PriorityWeakReferenceList list, GridEventProcessMode processMode)
   at Telerik.WinControls.UI.GridViewEventProcessEntity.ProcessEvent(GridViewEvent gridEvent)
   at Telerik.WinControls.UI.GridViewSynchronizationService.NotifyListeners(GridViewEvent gridEvent)
   at Telerik.WinControls.UI.GridViewSynchronizationService.FlushEvents()
   at Telerik.WinControls.UI.GridViewSynchronizationService.DispatchEvent(GridViewEvent gridEvent)
   at Telerik.WinControls.UI.GridViewSynchronizationService.RaiseCurrentChanged(GridViewTemplate template, GridViewRowInfo row, GridViewColumn column, Boolean user)
   at Telerik.WinControls.UI.GridViewTemplate.CollectionView_CurrentChanged(Object sender, EventArgs e)
   at System.EventHandler.Invoke(Object sender, EventArgs e)
   at Telerik.WinControls.Data.RadCollectionView`1.OnCurrentChanged(EventArgs args)
   at Telerik.WinControls.Data.RadCollectionView`1.SetCurrentPositionCore(Int32 newPosition, Boolean forceNotify, CurrentChangeReason reason)
   at Telerik.WinControls.Data.RadListSource`1.InitializeCurrentItem()
   at Telerik.WinControls.Data.RadListSource`1.Initialize()
   at Telerik.WinControls.Data.RadListSource`1.Bind(Object dataSource, String dataMember)
   at Telerik.WinControls.Data.RadListSource`1.set_DataSource(Object value)
   at Telerik.WinControls.UI.GridViewTemplate.set_DataSource(Object value)
   at BugReproduction.ControlContainingGridView.set_DataSource(Object value) in ...\BugReproduction\BugReproduction\ControlContainingGridView.cs:line 42

Please refer to the attached gif file. You will notice that for the GridViewMaskBoxColumn  with numeric mask the filtering doesn't work. For the other columns each key stroke filters the grid rows.

Workaround: either use a GridViewDecimalColumn or change the default editor for the GridViewMaskBoxColumn :

Hi Team,

Can you please share sample or demo code for candlestick graph (C# winform).

Thanks

Hello Guys,

Good Evening , As per your suggestions i make my custom treeview node with LiteVisualElements .

In That Node i have taken one StackLayoutElement and RoundRectShape assigned to it but still panel shows corners instead of round edges,

i tried with different properties and styles but not get succeed , so please help me out.

here i have attached image of my node and "stackLayoutElement" code too.

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

Hi All,

Note:- I am using Bound RadTreeview. Bound with DataSource.

1 Take RadTreeview

2 Add Few nodes Like:

    ......Node A

    ......Node B

    ......Node C

    ............Node D

    ............Node E

3 Now Drag Node B and Drop it in Node C (As Node C's Child)

4 It throw Exception Error Msg  "Collection was modified; enumeration operation may not execute."

5  Now Try to Drag Node E and Drop it in Node B, again same error occurs

6 Full error screen i attached here.

Please reply as soon as possible.

To reproduce: Add a RadMultiColumnCombobox to the form, set the DropDownStyle property to DropDownList and clear the text. You will notice that the height of the control is not bigger than 5 px.

Workaround: set MinimumSize 

Me.RadMultiColumnComboBox1.MinimumSize = New Size(200, 23)

To reproduce: add a RadLabel and change its cursor to Hand.

 this.radLabel1.Cursor = Cursors.Hand;

The PixelatedHandCursor.png shows the poor quality of the cursor which should be improved.

Workaround: https://stackoverflow.com/questions/6016995/un-antialiased-hand-cursor-in-windows-forms-apps/6017174#6017174

    public class LinkLabelEx : RadLabel
    {
        private const int WM_SETCURSOR = 0x0020;
        private const int IDC_HAND = 32649;

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        private static extern IntPtr LoadCursor(IntPtr hInstance, int lpCursorName);

        [DllImport("user32.dll", CharSet = CharSet.Auto)]
        private static extern IntPtr SetCursor(IntPtr hCursor);

        protected override void WndProc(ref Message m)
        {
            if (m.Msg == WM_SETCURSOR)
            {
                // Set the cursor to use the system hand cursor
                SetCursor(LoadCursor(IntPtr.Zero, IDC_HAND));

                // Indicate that the message has been handled
                m.Result = IntPtr.Zero;
                return;
            }

            base.WndProc(ref m);
        }
    }

The ImprovedCursorRendering.png  shows the improved cursor. 

To reproduce: please run the application provided in the ticket. You will notice that RadGridView stops updating.

Workaround: use MethodInvoker for the update operation:

        private void readTicks()
        {
            DateTime now = DateTime.Now;
            Tick previouse = null;
            for (int i = 0; i < lines.Length; i++)
            {
                if (canceled)
                    return;

                var t = new Tick();

                try
                {
                    try
                    {
                        JsonConvert.PopulateObject(lines[i], t);
                    }
                    catch
                    {
                        continue;
                    }


                    var c = contracts[t.ContractId];
                    c.Row[(int)t.TickType] = t;
                    c.CurrentTickSetNr++;

                    if (this.radGridView1.InvokeRequired)
                    {
                        this.radGridView1.Invoke(new MethodInvoker(delegate { c.Fire(t); }));
                    }
                    else
                    {
                        c.Fire(t);
                    }

                    previouse = t;
                    OnTick?.Invoke(c.ConId, i);
                }
                catch (Exception e)
                {
                    Debug.WriteLine(e.Message);
                }
            }

            OnDone?.Invoke(this, new EventArgs());
        }