Currently, RadChartView offers exporting to a Bitmap in one of the following formats: https://docs.microsoft.com/en-us/dotnet/api/system.drawing.imaging.imageformat?view=netframework-4.8

It would be nice to have export functionality to  a vector image.

The same issue can be observed in a DPI-aware application on higher scaling
Workaround: set the RadControl.EnableDpiScaling property to false

public partial class Form1 : Form
{
    public Form1()
    {
        RadControl.EnableDpiScaling = false;

        InitializeComponent();

        LineSeries lineSeries = new LineSeries();
        lineSeries.DataPoints.Add(new CategoricalDataPoint(20, "Jan"));
        lineSeries.DataPoints.Add(new CategoricalDataPoint(22, "Apr"));
        lineSeries.DataPoints.Add(new CategoricalDataPoint(12, "Jul"));
        lineSeries.DataPoints.Add(new CategoricalDataPoint(19, "Oct"));
        this.radChartView1.Series.Add(lineSeries);

        LineSeries lineSeries2 = new LineSeries();
        lineSeries2.DataPoints.Add(new CategoricalDataPoint(18, "Jan"));
        lineSeries2.DataPoints.Add(new CategoricalDataPoint(15, "Apr"));
        lineSeries2.DataPoints.Add(new CategoricalDataPoint(17, "Jul"));
        lineSeries2.DataPoints.Add(new CategoricalDataPoint(22, "Oct"));
        this.radChartView1.Series.Add(lineSeries2);
        
        LassoZoomController lassoZoomController = new LassoZoomController();
        radChartView1.Controllers.Add(lassoZoomController);
    }

    private void radButton1_Click(object sender, EventArgs e)
    {
        this.radChartView1.ExportToImage(@"..\..\image.png", this.radChartView1.Size);
    }
}

The new controller should allow lasso selection of data points without zooming the view port.

https://demos.telerik.com/kendo-ui/radar-charts/radar-column

The attached proejct shows a sample implementation.

Workaround:

 Sub New()

     InitializeComponent()

     AddHandler Me.RadChartView1.CreateRenderer, AddressOf CreateRenderer
     
     AddHandler Me.RadChartView1.LabelFormatting, AddressOf LabelFormatting 
     Dim barSeries As New Telerik.WinControls.UI.BarSeries("Performance", "RepresentativeName")
     barSeries.ShowLabels = True

     barSeries.DataPoints.Add(New CategoricalDataPoint(177, "Harley"))
     barSeries.DataPoints.Add(New CategoricalDataPoint(128, "White"))
     barSeries.DataPoints.Add(New CategoricalDataPoint(143, "Smith"))
     barSeries.DataPoints.Add(New CategoricalDataPoint(111, "Jones"))
     barSeries.DataPoints.Add(New CategoricalDataPoint(118, "Marshall"))
     Me.RadChartView1.Series.Add(barSeries)
     Dim barSeries2 As New Telerik.WinControls.UI.BarSeries("Performance", "RepresentativeName")
     barSeries2.ShowLabels = True
     barSeries2.DataPoints.Add(New CategoricalDataPoint(153, "Harley"))
     barSeries2.DataPoints.Add(New CategoricalDataPoint(141, "White"))
     barSeries2.DataPoints.Add(New CategoricalDataPoint(130, "Smith"))
     barSeries2.DataPoints.Add(New CategoricalDataPoint(88, "Jones"))
     barSeries2.DataPoints.Add(New CategoricalDataPoint(109, "Marshall"))
     Me.RadChartView1.Series.Add(barSeries2)

 End Sub

 Private Sub LabelFormatting(sender As Object, e As Telerik.WinControls.UI.ChartViewLabelFormattingEventArgs)
     Dim dataPoint As CategoricalDataPoint = TryCast(e.LabelElement.DataPoint, CategoricalDataPoint)
     e.LabelElement.Text = "Value: " & Environment.NewLine & dataPoint.Value
     e.LabelElement.BackColor = Color.Yellow 
 End Sub

 Private Sub CreateRenderer(sender As Object, e As ChartViewCreateRendererEventArgs)
     e.Renderer = New CustomCartesianRenderer(TryCast(e.Area, CartesianArea))
 End Sub

 Public Class CustomCartesianRenderer
 Inherits CartesianRenderer

     Public Sub New(area As CartesianArea)
         MyBase.New(area)

     End Sub

     Protected Overrides Sub Initialize()
         MyBase.Initialize()

         For i As Integer = 0 To Me.DrawParts.Count - 1
             Dim labelPart As BarLabelElementDrawPart = TryCast(Me.DrawParts(i), BarLabelElementDrawPart)
             If labelPart IsNot Nothing Then
                 Me.DrawParts(i) = New CustomLabelElementDrawPart(DirectCast(labelPart.Element, BarSeries), Me)
             End If
         Next
     End Sub
 End Class

 Public Class CustomLabelElementDrawPart
 Inherits BarLabelElementDrawPart
     Public Sub New(owner As ChartSeries, renderer As IChartRenderer)
         MyBase.New(owner, renderer)
     End Sub

     Public Overrides Sub Draw()
         For Each dataPointElement As DataPointElement In Me.Element.Children
             For Each label As LabelElement In dataPointElement.Children
                 label.ForeColor = Color.Transparent
             Next
         Next

         MyBase.Draw()
         Dim graphics As Graphics = TryCast(Me.Renderer.Surface, Graphics)
         Dim radGraphics As New RadGdiGraphics(graphics)
         Dim slot As RadRect
         Dim rect As Rectangle
         Dim stringFormat As New StringFormat()
         stringFormat.Alignment = StringAlignment.Center
         stringFormat.LineAlignment = StringAlignment.Center

         For Each dataPointElement As DataPointElement In Me.Element.Children
             For Each label As LabelElement In dataPointElement.Children
                 label.ForeColor = Color.Transparent
                 slot = label.GetLayoutSlot()
                 slot = AdjustLayoutSlot(slot, label.DataPointElement)
                 rect = ChartRenderer.ToRectangle(slot)
                 Using brush As Brush = New SolidBrush(Color.Red)
                     Dim drawLocation As New PointF()
                     drawLocation.X = rect.X + label.Padding.Left
                     drawLocation.Y = rect.Y + label.Padding.Top

                     graphics.DrawString(label.Text, label.Font, brush, rect, stringFormat)
                 End Using
             Next
         Next
     End Sub
 End Class

When the legend has many items a scrollbar should appear.

Add Range series similar to those provided by WPF/SL

http://demos.telerik.com/silverlight/#ChartView/Gallery/Range

The lasso controller should zoom vertically as well.

It would be very helpful if you either added ScaleBreaks (as in the deprecated RadChart control - http://www.telerik.com/help/winforms/chart-features-scale-breaks.html) or provided an alternative way. I use them a great deal with bar charts and logarithmic scales are not optimal.

Currently, when you zoom in and out, the position the mouse is initially hovering is not kept, while it should

ADD. RadChartView - add waterfall series type.

Add the ability a user to be able to use a Custom DashStyle in the following scenario:

this.Chart.ShowLegend = true;
this.Chart.Series.Add(new LineSeries() { LegendTitle = "DDDD" });
this.Chart.ChartElement.LegendElement.Items[0].Element.BorderDashStyle = System.Drawing.Drawing2D.DashStyle.Custom;

for (int i = 0; i < 10; i++)
{
    this.Chart.Series[0].DataPoints.Add(i);
}

The following article describes how to use a Custom DashStyle: How to: Draw a Custom Dashed Line