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;
		}
	}

en Telerik.WinControls.UI.BestFitHelper.SetColumnWidth(GridViewColumn column, Single desiredWidth)
   en Telerik.WinControls.UI.BestFitHelper.BestFitColumnCore(GridViewColumn column, BestFitColumnMode mode)
   en Telerik.WinControls.UI.BestFitHelper.ProcessRequests()
   en Telerik.WinControls.UI.GridTableElement.UpdateAll()
   en Telerik.WinControls.UI.GridTableElement.UpdateViewCore(Object sender, DataViewChangedEventArgs args)
   en Telerik.WinControls.UI.GridTableElement.UpdateView(Object sender, DataViewChangedEventArgs args)
   en Telerik.WinControls.UI.GridTableElement.ProcessTemplateEvent(GridViewEvent eventData)
   en Telerik.WinControls.UI.GridTableElement.Telerik.WinControls.UI.IGridViewEventListener.ProcessEvent(GridViewEvent eventData)
   en Telerik.WinControls.UI.GridViewEventProcessEntity.ProcessCollection(GridViewEvent gridEvent, PriorityWeakReferenceList list, GridEventProcessMode processMode)
   en Telerik.WinControls.UI.GridViewEventProcessEntity.ProcessEvent(GridViewEvent gridEvent)
   en Telerik.WinControls.UI.GridViewSynchronizationService.NotifyListeners(GridViewEvent gridEvent)
   en Telerik.WinControls.UI.GridViewSynchronizationService.FlushEvents()
   en Telerik.WinControls.UI.GridViewSynchronizationService.DispatchEvent(GridViewEvent gridEvent)
   en Telerik.WinControls.UI.GridViewSynchronizationService.DispatchEvent(GridViewTemplate template, GridViewEvent eventData, Boolean postUI)
   en Telerik.WinControls.UI.GridViewTemplate.DispatchEvent(GridViewEvent gridEvent, Boolean postUI)
   en Telerik.WinControls.UI.GridViewTemplate.DispatchDataViewChangedEvent(Object sender, DataViewChangedEventArgs args)
   en Telerik.WinControls.UI.GridViewTemplate.OnViewChanged(Object sender, DataViewChangedEventArgs e)
   en Telerik.WinControls.UI.MasterGridViewTemplate.OnViewChanged(Object sender, DataViewChangedEventArgs e)
   en Telerik.WinControls.UI.GridViewTemplate.CollectionView_CollectionChanged(Object sender, NotifyCollectionChangedEventArgs e)
   en Telerik.WinControls.Data.RadCollectionView`1.OnCollectionChanged(NotifyCollectionChangedEventArgs args)
   en Telerik.WinControls.Data.RadDataView`1.RebuildData(Boolean notify)
   en Telerik.WinControls.Data.RadDataView`1.RefreshOverride()
   en Telerik.WinControls.Data.RadDataView`1.ProcessCollectionChanged(NotifyCollectionChangedEventArgs args)
   en Telerik.WinControls.Data.RadCollectionView`1.source_CollectionChanged(Object sender, NotifyCollectionChangedEventArgs e)
   en Telerik.WinControls.Data.NotifyCollectionChangedEventHandler.Invoke(Object sender, NotifyCollectionChangedEventArgs e)
   en Telerik.WinControls.Data.RadListSource`1.OnCollectionChanged(NotifyCollectionChangedEventArgs e)
   en Telerik.WinControls.Data.RadListSource`1.EndUpdate(Boolean notifyUpdates)
   en Telerik.WinControls.Data.RadListSource`1.Initialize()
   en Telerik.WinControls.Data.RadListSource`1.Bind(Object dataSource, String dataMember)
   en Telerik.WinControls.Data.RadListSource`1.set_DataSource(Object value)
   en Telerik.WinControls.UI.GridViewTemplate.set_DataSource(Object value)
   en Telerik.WinControls.UI.RadGridView.set_DataSource(Object value)

public Form1()
{
    InitializeComponent();
    this.radDateTimePicker1.MaskProviderCreated += RadDateTimePicker1_MaskProviderCreated;           
    this.radDateTimePicker1.DateTimePickerElement.ShowCurrentTime = false;
    this.radDateTimePicker1.Format = System.Windows.Forms.DateTimePickerFormat.Custom;
    this.radDateTimePicker1.Culture = new System.Globalization.CultureInfo("en-US");
    this.radDateTimePicker1.CustomFormat = "hh:mm:ss tt";
    this.radDateTimePicker1.Value = new System.DateTime(2025, 6, 12, 12, 4, 34, 562);
}