public partial class TestForm: Form
	{
		private readonly DataView _view;

		public TestForm()
		{
			InitializeComponent();

			_view = new DataView(LoadTable(true));
			_grid.ColumnCount = _view.Table.Columns.Count;
			_grid.RowCount = _view.Count;
			_grid.AllowAddNewRow = true;
			_grid.SelectionMode = VirtualGridSelectionMode.FullRowSelect;
		}

		static private DataTable LoadTable(bool fill)
		{
			var table = new DataTable();
			table.Columns.Add("Number", typeof(int));
			
			if (fill)
				for(int i = 0; i < 20; i++)
					table.Rows.Add(i);
			
			return table;
		}


		#region Windows Form Designer generated code

		/// <summary>
		/// Required method for Designer support - do not modify
		/// the contents of this method with the code editor.
		/// </summary>
		private void InitializeComponent()
		{
			this._grid = new Telerik.WinControls.UI.RadVirtualGrid();
			((System.ComponentModel.ISupportInitialize)(this._grid)).BeginInit();
			this.SuspendLayout();
			// 
			// _grid
			// 
			this._grid.Dock = System.Windows.Forms.DockStyle.Fill;
			this._grid.Location = new System.Drawing.Point(0, 0);
			this._grid.MultiSelect = true;
			this._grid.Name = "_grid";
			this._grid.SelectionMode = Telerik.WinControls.UI.VirtualGridSelectionMode.FullRowSelect;
			this._grid.Size = new System.Drawing.Size(800, 450);
			this._grid.TabIndex = 0;
			this._grid.CellValueNeeded += new Telerik.WinControls.UI.VirtualGridCellValueNeededEventHandler(this._grid_CellValueNeeded);
			this._grid.UserDeletedRow += new Telerik.WinControls.UI.VirtualGridRowsEventHandler(this._grid_UserDeletedRow);
			// 
			// TestForm
			// 
			this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
			this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
			this.ClientSize = new System.Drawing.Size(800, 450);
			this.Controls.Add(this._grid);
			this.Name = "TestForm";
			this.Text = "TestForm";
			((System.ComponentModel.ISupportInitialize)(this._grid)).EndInit();
			this.ResumeLayout(false);

		}

		#endregion

		private Telerik.WinControls.UI.RadVirtualGrid _grid;

		private void _grid_CellValueNeeded(object sender, Telerik.WinControls.UI.VirtualGridCellValueNeededEventArgs e)
		{
			if (e.ColumnIndex < 0)
				return;

			if (e.RowIndex < 0)
			{
				e.FieldName = _view.Table.Columns[e.ColumnIndex].ColumnName;
				if (e.RowIndex == RadVirtualGrid.HeaderRowIndex)
					e.Value = e.FieldName;
			}
			else if (e.RowIndex < _view.Count)
			{
				e.Value = _view[e.RowIndex][e.ColumnIndex];
			}
		}

		private void _grid_UserDeletedRow(object sender, Telerik.WinControls.UI.VirtualGridRowsEventArgs e)
		{
			var rowIndexes = e.RowIndices.Distinct().OrderByDescending(i => i).ToList(); // Off topic: I have seen duplicate row indexes in this row collection. And unsorted. Is that by design?
			if (rowIndexes.Count == _view.Count)
			{
				_view.Table.Rows.Clear();
			}
			else
			{
				foreach(var index in rowIndexes)
					_view[index].Delete();
			}

			_grid.RowCount = _view.Count;
		}
	}

System.SystemException: 'System.MethodAccessException: Attempt by security transparent method 'Telerik.Pdf.Gdi.GdiFontEnumerator.get_FamilyNames()' to call native code through method 'Telerik.WinControls.NativeMethods.EnumFontFamiliesEx(IntPtr, LOGFONT, FontEnumDelegate, Int32, Int32)' failed.  Methods must be security critical or security safe-critical to call native code.
   at Telerik.Pdf.Gdi.GdiFontEnumerator.get_FamilyNames()
   at Telerik.Apoc.Pdf.FontSetup.AddSystemFonts(FontType fontType)
   at Telerik.Apoc.Render.Pdf.PdfRenderer.SetupFontInfo(FontInfo fontInfo)
   at Telerik.Apoc.Fo.FOTreeBuilder.Parse(XmlReader reader)'

Stream outputStream = new FileStream("path", FileMode.OpenOrCreate, FileAccess.ReadWrite)

radToggleSwitch1.SetToggleState(newValue: false, animate: false);

            this.radToggleSwitch1.AllowAnimation = false;
            this.radToggleSwitch1.Toggle();

this.radRichTextEditor1.Text = null;

    Dim dt As New DataTable
    Sub New()

        InitializeComponent()

        dt.Columns.Add("Id", GetType(Integer))
        dt.Columns.Add("Name", GetType(String))
        For index = 1 To 10000
            dt.Rows.Add(index, Guid.NewGuid.ToString())

        Next
        Me.RadGridView1.DataSource = dt
        Me.RadGridView1.AutoSizeColumnsMode = Telerik.WinControls.UI.GridViewAutoSizeColumnsMode.Fill

        Me.RadGridView1.AllowSearchRow = True

    End Sub

    Private Sub RadButton1_Click(sender As Object, e As EventArgs) Handles RadButton1.Click
        For index = 1 To 50
            dt.Rows.RemoveAt(0)
        Next
    End Sub

   at Telerik.WinControls.UI.MasterGridViewTemplate.set_CurrentRow(GridViewRowInfo value)
   at Telerik.WinControls.UI.RadGridView.set_CurrentRow(GridViewRowInfo value)
   at Telerik.WinControls.UI.GridViewSearchRowInfo.SetCurrent(GridSearchResultCellInfo cell)
   at Telerik.WinControls.UI.GridViewSearchRowInfo.SetCurrent(GridSearchResultCellInfo cell, Boolean checkInvokeRequired)
   at Telerik.WinControls.UI.GridViewSearchRowInfo.SelectNextSearchResult()
   at Telerik.WinControls.UI.GridViewSearchRowInfo.Search(String criteria)
   at Telerik.WinControls.UI.GridViewSearchRowInfo.Telerik.WinControls.UI.IGridViewEventListener.PostProcessEvent(GridViewEvent eventData)
   at Telerik.WinControls.UI.GridViewEventProcessEntity.ProcessCollection(GridViewEvent gridEvent, PriorityWeakReferenceList list, GridEventProcessMode processMode)
   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.DispatchEvent(GridViewTemplate template, GridViewEvent eventData, Boolean postUI)
   at Telerik.WinControls.UI.GridViewRowCollection.DispatchDataViewChangedEvent(DataViewChangedEventArgs args, GridEventType type)
   at Telerik.WinControls.UI.GridViewRowCollection.ListSource_CollectionChanged(Object sender, NotifyCollectionChangedEventArgs e)
   at Telerik.WinControls.Data.NotifyCollectionChangedEventHandler.Invoke(Object sender, NotifyCollectionChangedEventArgs e)
   at Telerik.WinControls.Data.RadListSource`1.OnCollectionChanged(NotifyCollectionChangedEventArgs e)
   at Telerik.WinControls.Data.RadListSource`1.RemoveItem(Int32 index)
   at Telerik.WinControls.Data.RadListSource`1.currencyManager_ListChanged(Object sender, ListChangedEventArgs e)
   at System.Windows.Forms.CurrencyManager.OnListChanged(ListChangedEventArgs e)
   at System.Windows.Forms.CurrencyManager.List_ListChanged(Object sender, ListChangedEventArgs e)
   at System.Windows.Forms.BindingSource.OnListChanged(ListChangedEventArgs e)
   at System.Windows.Forms.BindingSource.InnerList_ListChanged(Object sender, ListChangedEventArgs e)
   at System.ComponentModel.BindingList`1.OnListChanged(ListChangedEventArgs e)
   at System.ComponentModel.BindingList`1.FireListChanged(ListChangedType type, Int32 index)
   at System.ComponentModel.BindingList`1.RemoveItem(Int32 index)
   at System.Collections.ObjectModel.Collection`1.Remove(T item)
   at System.Collections.ObjectModel.Collection`1.System.Collections.IList.Remove(Object value)
   at System.Windows.Forms.BindingSource.Remove(Object value)