Last Updated: 01 Mar 2024 13:13 by ADMIN

PerformClick method of RadButtonElement is sending next error:

System.InvalidCastException: 'Unable to cast object of type 'System.EventArgs' to type 'System.Windows.Forms.MouseEventArgs'.

Find my code below:

private void btnAddField_Click(object sender, EventArgs e)
    RadDiagramShape sourceShape = new RadDiagramShape()
        Text = "source",
        Shape = new RoundRectShape(5),
        BackColor = Color.Red

    sourceShape.Position = new Telerik.Windows.Diagrams.Core.Point(150, 100);

    sourceShape.IsSelected = true;
    RadButtonElement additionalContent = Telerik.WinControls.UI.Diagrams.Primitives.ItemInformationAdorner.GetAdditionalContent(
                                            this.radDiagram.DiagramElement.ItemInformationAdorner) as RadButtonElement;


What I want is to display the SettingsPane automatically when adding a RadDiagramShape item in a RadDiagram


Last Updated: 20 Feb 2024 12:26 by ADMIN

Hi- When I add a Rad context menu to a RadToolbarForm, the toolbar vanishes from the designer after a build.  This is new behavior because I have other context menus that I had previously added to the form.  If I drag a RadContextMenu from the toolkit, or I copy/paste an existing context menu, the toolbar disappears after a build.  I am running the latest release (2024.1.130) and toolkit config (although this also happens when running the previous Telerik release)

I tried closing the designer before the build and the toolbar still disappears.  Doing a Clean before build has no effect.  This form is inherited from a simple RadToolbar form (no controls except the toolbar).  The toolbar is still listed in the list of controls for the form

Ha!  Just found out what's happening.  It's deleting the toolbar configuration code from the designer code.  Everything below is gone.  If I add it back in, then do anything with the new context menu, like rename it, it gets removed again

            // RadToolbarFormControl1
            RadToolbarFormControl1.AutoSize = false;
            RadToolbarFormControl1.CenterItems.AddRange(new Telerik.WinControls.RadItem[] { RadLabelElement1, RadButtonElement_Task_New, RadButtonElement_Task_Edit, RadButtonElement_Task_Delete, RadCheckBoxElement_ShowCompleted });
            RadToolbarFormControl1.CenterItemsVerticalAlignment = Telerik.WinControls.UI.RadVerticalAlignment.Bottom;
            RadToolbarFormControl1.FarItems.AddRange(new Telerik.WinControls.RadItem[] { RadLabelElement_WorkHours, RadLabelElement_Work_StartDate, RadLabelElement_Work_EndDate, RadButtonElement_SelectDates, RadButtonElement_Invoices, RadButtonElement_Summary });
            RadToolbarFormControl1.NearItems.AddRange(new Telerik.WinControls.RadItem[] { RadLabelElement2, RadLabelElement_Projects, RadButtonElement_New, RadButtonElement_Edit, RadButtonElement_Delete, RadButtonElement_Refresh });
            RadToolbarFormControl1.ShowText = false;
            RadToolbarFormControl1.Size = new Size(1804, 52);


Here's my dev environment:

Microsoft Visual Studio Community 2022
Version 17.8.7
Microsoft .NET Framework
Version 4.8.09037

Installed Version: Community

ActiveReports 16
The first report writer for Microsoft .NET

ASP.NET and Web Tools   17.8.358.6298
ASP.NET and Web Tools

Azure App Service Tools v3.0.0   17.8.358.6298
Azure App Service Tools v3.0.0

C# Tools   4.8.0-7.23572.1+7b75981cf3bd520b86ec4ed00ec156c8bc48e4eb
C# components used in the IDE. Depending on your project type and settings, a different version of the compiler may be used.

Code Converter   1.0
Code Converter Extension Details

Common Azure Tools   1.10
Provides common services for use by Azure Mobile Services and Microsoft Azure Tools.

Microsoft JVM Debugger   1.0
Provides support for connecting the Visual Studio debugger to JDWP compatible Java Virtual Machines

NuGet Package Manager   6.8.1
NuGet Package Manager in Visual Studio. For more information about NuGet, visit

Progress Telerik UI for WinForms Extension   2023.3.1110.93
Progress® Telerik® UI for WinForms Extension

TypeScript Tools   17.0.20920.2001
TypeScript Tools for Microsoft Visual Studio

Visual Basic Tools   4.8.0-7.23572.1+7b75981cf3bd520b86ec4ed00ec156c8bc48e4eb
Visual Basic components used in the IDE. Depending on your project type and settings, a different version of the compiler may be used.

Visual F# Tools   17.8.0-beta.23475.2+10f956e631a1efc0f7f5e49c626c494cd32b1f50
Microsoft Visual F# Tools

Visual Studio IntelliCode   2.2
AI-assisted development for Visual Studio.


Last Updated: 16 Feb 2024 22:25 by ADMIN

I can't provide a project or even code snippets that would make sense out of context because the code base is too complex for an easy replication to be setup.

We are trying various things like calling Refresh, Update.


Hoping this is something you've encountered before and have some suggestions.

Last Updated: 16 Feb 2024 22:24 by ADMIN

C#. net core 6, winforms application, TekerikNuGet3 package source, UI.for.WinForms.AllControls.NetCore package 2022.2.622

I am trying to export selected cells from a RadGridView as a csv file.

When using "var exporter = new ExportToCSV(Dgv)" then "exporter.RunExport(fileName);" writes the csv file correctly. It exports every cell.

It doesn't support exporting selections so I wrote a function to do this . The one below is what I used in my project to test what I was doing. It initially writes the csv to a worksheet and wrote that using formatprovider to file, then I just created a stringbuilder adding quotes and appended that to the file afterwards.

Writing the worksheet, the csv values haven't been quoted, plus number fields have had leading zeros removed which proves to be a problem when telephone numbers are stored in a field.

So I googled and found the Settings property which is there to set csv options. But they are private, not public therefore I can't set up the csv propertly.

private void radButton1_Click(object sender, EventArgs e)

    var workbook = new Workbook();
    var worksheet = workbook.Worksheets.Add();

    var rowIndex = 0;
    var columnIndex = -1;
    var sb = new StringBuilder();
    var prevColumnIndex = -1;

    // ForEach cell are accessed vertically then horizontally.
    foreach (var cell in Dgv.SelectedCells)
      // Cell is included in selection even if it's invisible
      // so check visibility and ignore if it isnt
      if (!cell.ColumnInfo.IsVisible) continue;

      // At bottom of column, rownum will change. Watch for this
      // and reset x and y values
      var rowNum = cell.RowInfo.Index;
      if (rowNum != prevColumnIndex)
        prevColumnIndex = rowNum;
        rowIndex = 0;
      else if (!string.IsNullOrEmpty(sb.ToString()))

      var value = cell.Value;
      worksheet.Cells[columnIndex, rowIndex++ ].SetValue(value.ToString());

    var fileName = @"C:\temp\SampleFile.csv";

    IWorkbookFormatProvider formatProvider = new CsvFormatProvider();
    using var output = new FileStream(fileName, FileMode.Create);
    formatProvider.Export(workbook, output);

    // Write contents of sb to the file for comparison sake
    File.AppendAllText(fileName, sb.ToString());


Last Updated: 16 Feb 2024 22:22 by ADMIN

I just upgraded to the latest version of Telerik products and facing the issues described below.

When dragging and drop Telerik UI objects from the toolbar on a form, the dialog box below is displayed with question but there is no button to click to answer the question and I don't where to stop it.

See screenshot attached.

Last Updated: 16 Feb 2024 22:20 by ADMIN
Created by: Ian
Comments: 2
Category: ChartView
Type: Feature Request
Some other charting frameworks support ‘dynamic’ graphs/diagrams, where the graph shows nodes and links, and the user can drag the nodes around the page, and the other nodes are pulled around it. This is a great way to visualise and explore this kind of node+link data. Its also a great way to sell and app, as it looks cool.
Last Updated: 16 Feb 2024 22:19 by ADMIN
Created by: Haithem
Comments: 2
Category: PdfViewer
Type: Bug Report



I am have a problem with pdf wiewer when the PDF file contains an images , it is slow in movement and it is difficult to navigate between pages. Is it possible to fix this problem 



Last Updated: 16 Feb 2024 22:18 by ADMIN

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.


Last Updated: 16 Feb 2024 20:34 by ADMIN

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.

spnlControls = new StackLayoutElement();
            spnlControls.Orientation = Orientation.Horizontal;
            spnlControls.NotifyParentOnMouseInput = true;
            spnlControls.DrawFill = true;
            spnlControls.DrawBorder = true;
            spnlControls.Shape = new RoundRectShape(4);
            spnlControls.BackColor = Color.Transparent;
            spnlControls.BackColor2 = Color.Transparent;
            spnlControls.BackColor3 = Color.Transparent;
            spnlControls.BackColor4 = Color.Transparent;
            spnlControls.BorderGradientStyle = GradientStyles.Solid;
Last Updated: 16 Feb 2024 20:33 by ADMIN
Created by: James
Comments: 2
Category: UI for WinForms
Type: Bug Report

Zooming in will throw an Exception that crashes the program.

The ZoomLevel needed to cause the exception is dependent on the area of the RadMap selected.

Provider: BingRestMapProvider

ImagerySet AerialWithLabelsOnDemand



Zooming in over Antarctica, Exception thrown zooming in at MapElement.ZoomLevel 14.


Zooming in over Australia, Exception thrown zooming in at MapElement.ZoomLevel 21.


Last Updated: 16 Feb 2024 20:32 by ADMIN
Created by: Kaan
Comments: 2
Category: UI for WinForms
Type: Feature Request


I want to hide some columns of the table I received from Excel on RadGridView.

Last Updated: 16 Feb 2024 20:31 by ADMIN
Created by: Larry
Comments: 2
Category: RichTextEditor
Type: Bug Report
There appears to be an issue when adding Comments that overlap each other. I will attach a video to my next reply that shows how to replicate the issue.
Last Updated: 16 Feb 2024 20:30 by ADMIN
Fatching data from sql database in gridViewCommboBoxColumn select the value then retrieve data other column in the same Rows windows application in
Last Updated: 16 Feb 2024 20:28 by ADMIN
The filter UI controls in ASP.NET Core and MVC are really nice, see filter. Can you include the same controls and UI be included in Winforms and WPF?
Last Updated: 16 Feb 2024 20:26 by ADMIN
Created by: Mario
Comments: 4
Category: UI for WinForms
Type: Feature Request

Hi everybody


I m try use the class CustomDragandDrop on radtreeview but i have a issue, 

if i use the next example, i dont have any problem:


   protected void BindRadTreeView()
            DataTable dt = new DataTable();
            dt.Columns.Add("Id", typeof(string));
            dt.Columns.Add("Title", typeof(string));
            dt.Columns.Add("ParentId", typeof(string));

            string parentId = string.Empty;
            string childId = string.Empty;
            for (int i = 0; i < 2; i++)
                parentId = Guid.NewGuid().ToString();
                dt.Rows.Add(parentId, "Node" + i, null);
                for (int j = 0; j < 5; j++)
                    childId = Guid.NewGuid().ToString();
                    dt.Rows.Add(childId, "SubNode" + i + "." + j, parentId);

            this.radTreeView1.ChildMember = "Id";
            this.radTreeView1.ParentMember = "ParentId";
            this.radTreeView1.DisplayMember = "Title";
            this.radTreeView1.DataSource = dt;



i can drag and drop correctly


but the problem is when i binding the Radtreeview



    protected void llenatreeview1() {

            dtTablas = dat.consultaBD();

            DataTable dt = new DataTable();
            dtCopi.Columns.Add("Id", typeof(string));
            dtCopi.Columns.Add("Title", typeof(string));
            dtCopi.Columns.Add("ParentId", typeof(string));

            string parentId = string.Empty;
            string Id = string.Empty;
            string title = string.Empty;
            foreach (DataRow row in dtTablas.Rows)
                parentId = row["ParentId"].ToString();     

                Id = row["Id"].ToString();
                title = row["Title"].ToString();

                if (parentId == "")
                    dt.Rows.Add(Id, title, null);
                    dt.Rows.Add(Id, title, parentId);

            radTreeView2.ChildMember = "Id";
            radTreeView2.ParentMember = "ParentId";
            radTreeView2.DisplayMember = "Title";
            radTreeView2.DataSource = dt;

first is freeze and then appears the error.

when i drag and drop appears then next error:



what am I doing wrong please your help. thanks
Last Updated: 16 Feb 2024 20:24 by ADMIN
Created by: Ian
Comments: 2
Category: UI for WinForms
Type: Feature Request

GridView has a default text alignment for new columns as 'MiddleCenter'.

Default alignment for new GridViewDataRowInfo is 'left'.

Please can these be the same ?

Last Updated: 16 Feb 2024 19:59 by ADMIN
Created by: Robyn
Comments: 2
Category: UI for WinForms
Type: Bug Report

Hi there,


We have recently found a bug on both the RadDocument and Rad Rich Text Editor. Created a RTF document via the RadRichText Editor. The RTF document contains a table. When the document is saved and loaded from the same form, it is displaying correctly, however when loaded from a different form, it seems to have shrunk and lost the column width, thus having long and skinny columns.

We have set the fixed column width on the table, however this did not seem to solve the issue.

I have attached two screenshots for reference. One with the correct looking table, and one with the long and skinny columns.

Is there a workaround, or is this a known bug?


Correct table:



Long and skinny columns:


Currently on Telerik Winforms version 2018.3.1016.40


Kind regards,



Last Updated: 16 Feb 2024 19:56 by ADMIN

I have a form which contains TreeView control. I need to convert it to RadTreeView. So I replaced TreeView control with RadTreeView and TreeNode with RadTreeNode in the code. I found that the events in both are different, so tried to replace the events with similar events in RadTree.

Following are the events that I have replaced in my code :


        Private Sub TreeView1_AfterExpand(ByVal sender As Object, ByVal e As System.Windows.Forms.TreeViewEventArgs) Handles tvMain.AfterExpand

Replaced by -

        Private Sub TreeView1_AfterExpand(ByVal sender As Object, ByVal e As Telerik.WinControls.UI.RadTreeViewEventArgs) Handles tvMain.NodeExpandedChanged   


            Private Sub TreeView1_AfterCollapse(ByVal sender As Object, ByVal e As System.Windows.Forms.TreeViewEventArgs) Handles tvMain.AfterCollapse

  Replaced by -  

            Private Sub TreeView1_AfterCollapse(ByVal sender As Object, ByVal e As Telerik.WinControls.UI.RadTreeViewEventArgs) Handles tvMain.NodeExpandedChanged

and included Expanded flag to check if it is expand or collapse.

Here, I noticed unwanted firing of this replaced event when compared to the old event, but I handled it using the Expanded flag.


        Private Sub tvMain_AfterSelect(ByVal sender As System.Object, ByVal e As System.Windows.Forms.TreeViewEventArgs) Handles tvMain.AfterSelect

Replaced by -

        Private Sub tvMain_AfterSelect(ByVal sender As System.Object, ByVal e As Telerik.WinControls.UI.RadTreeViewEventArgs) Handles tvMain.SelectedNodesChanged

This event gets fired twice while clicking on a node.

My main issues are,

  • During the initial load of the form, the tree gets populated and at that time the select event (mentioned in point 3) fires automatically in my old project in which TreeView is used. But in the new project, during the load of the form the replaced event is not fired.
  • Similarly, when I clicks a node , the replaced select event fires twice. After that I have a button in the same form which works like, when we click on a node and then click on the add button it will add a new node to the tree under the selected node. Now the functionality of the button doesnt work because, within the click function of add button, treeView1.selectedNode is 'Nothing'. Eventhough the select event is fired on clicking the node, the selectednode is 'Nothing' inside the click function of add button.
Last Updated: 16 Feb 2024 19:51 by ADMIN
Created by: Lior
Comments: 2
Category: GridView
Type: Bug Report

i am getting a null reference exception with the following call stack:


Description: The process was terminated due to an unhandled exception.

Exception Info: System.NullReferenceException

   at Telerik.WinControls.UI.TableViewRowLayoutBase.GetRowHeight(Telerik.WinControls.UI.GridViewRowInfo)

   at Telerik.WinControls.UI.RowElementProvider.GetElementSize(Telerik.WinControls.UI.GridViewRowInfo)

   at Telerik.WinControls.UI.ItemScroller`1[[System.__Canon, mscorlib, Version=, Culture=neutral, PublicKeyToken=b77a5c561934e089]].GetScrollHeight(System.__Canon)

   at Telerik.WinControls.UI.ItemScroller`1[[System.__Canon, mscorlib, Version=, Culture=neutral, PublicKeyToken=b77a5c561934e089]].ScrollDown(Int32)

   at Telerik.WinControls.UI.ItemScroller`1[[System.__Canon, mscorlib, Version=, Culture=neutral, PublicKeyToken=b77a5c561934e089]].ScrollTo(Int32)

   at Telerik.WinControls.UI.ItemScroller`1[[System.__Canon, mscorlib, Version=, Culture=neutral, PublicKeyToken=b77a5c561934e089]].scrollbar_ValueChanged(System.Object, System.EventArgs)

   at Telerik.WinControls.UI.RadScrollBarElement.OnValueChanged(Int32, Int32)

   at Telerik.WinControls.UI.RadScrollBarElement.set_Value(Int32)

   at Telerik.WinControls.UI.ItemScroller`1[[System.__Canon, mscorlib, Version=, Culture=neutral, PublicKeyToken=b77a5c561934e089]].UpdateScrollValue()

   at Telerik.WinControls.UI.ItemScroller`1[[System.__Canon, mscorlib, Version=, Culture=neutral, PublicKeyToken=b77a5c561934e089]].UpdateScrollRange()

   at Telerik.WinControls.UI.RowScroller.UpdateScrollRange()

   at Telerik.WinControls.UI.GridTableElement.UpdateNoDataText()

   at Telerik.WinControls.UI.GridTableElement.UpdateAll()

   at Telerik.WinControls.UI.GridTableElement.UpdateViewCore(System.Object, Telerik.WinControls.UI.DataViewChangedEventArgs)

   at Telerik.WinControls.UI.GridTableElement.UpdateView(System.Object, Telerik.WinControls.UI.DataViewChangedEventArgs)

   at Telerik.WinControls.UI.GridTableElement.ProcessTemplateEvent(Telerik.WinControls.UI.GridViewEvent)

   at Telerik.WinControls.UI.GridTableElement.Telerik.WinControls.UI.IGridViewEventListener.ProcessEvent(Telerik.WinControls.UI.GridViewEvent)

   at Telerik.WinControls.UI.GridViewEventProcessEntity.ProcessCollection(Telerik.WinControls.UI.GridViewEvent, Telerik.WinControls.UI.PriorityWeakReferenceList, Telerik.WinControls.UI.GridEventProcessMode)

   at Telerik.WinControls.UI.GridViewEventProcessEntity.ProcessEvent(Telerik.WinControls.UI.GridViewEvent)

   at Telerik.WinControls.UI.GridViewSynchronizationService.NotifyListeners(Telerik.WinControls.UI.GridViewEvent)

   at Telerik.WinControls.UI.GridViewSynchronizationService.FlushEvents()

   at Telerik.WinControls.UI.GridViewSynchronizationService.DispatchEvent(Telerik.WinControls.UI.GridViewEvent)

   at Telerik.WinControls.UI.GridViewSynchronizationService.DispatchEvent(Telerik.WinControls.UI.GridViewTemplate, Telerik.WinControls.UI.GridViewEvent, Boolean)

   at Telerik.WinControls.UI.GridViewTemplate.DispatchEvent(Telerik.WinControls.UI.GridViewEvent, Boolean)

   at Telerik.WinControls.UI.GridViewTemplate.DispatchDataViewChangedEvent(System.Object, Telerik.WinControls.UI.DataViewChangedEventArgs)

   at Telerik.WinControls.UI.GridViewTemplate.OnViewChanged(System.Object, Telerik.WinControls.UI.DataViewChangedEventArgs)

   at Telerik.WinControls.UI.MasterGridViewTemplate.OnViewChanged(System.Object, Telerik.WinControls.UI.DataViewChangedEventArgs)

   at Telerik.WinControls.UI.GridViewTemplate.EndUpdate(Boolean, Telerik.WinControls.UI.DataViewChangedEventArgs)

   at Telerik.WinControls.UI.MasterGridViewTemplate.EndUpdate(Boolean, Telerik.WinControls.UI.DataViewChangedEventArgs)

   at Telerik.WinControls.UI.GridViewTemplate.set_RowCount(Int32)

   at Telerik.WinControls.UI.RadGridView.set_RowCount(Int32)

   at Communication_Logger.frmCommunicationLogger.RadRibbonForm1_OnDataReceived(Communication_Logger.Data)

   at Communication_Logger.ChannelClass.Serial_DataReceived(System.Object, System.IO.Ports.SerialDataReceivedEventArgs)

   at System.IO.Ports.SerialPort.CatchReceivedEvents(System.Object, System.IO.Ports.SerialDataReceivedEventArgs)

   at System.IO.Ports.SerialStream+EventLoopRunner.CallReceiveEvents(System.Object)

   at System.Threading.QueueUserWorkItemCallback.WaitCallback_Context(System.Object)

   at System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)

   at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)

   at System.Threading.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem()

   at System.Threading.ThreadPoolWorkQueue.Dispatch()

   at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback()


the setup is a dotNet 4.5.2 winforms application with RadGridView in virtual mode.

The exception occur when the application is left working for days (2 in this case) without any user interaction.

The application normally updates a list that is used by the gridview, the list records are added and removed continuously, the grid view RowCount is updated via a timer.

i suspect that the RowCount reported at one point in time doesn't match the list size as it is trimmed, and therfore the GetRowHeight fails as the data doesn't exist - can this be handled in the gridview - to avoid a termination of the process due to the exception ?





Last Updated: 16 Feb 2024 19:49 by ADMIN
Created by: avani
Comments: 2
Category: TreeView
Type: Bug Report

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;



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

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