How to change the chart item ControlTemplate?

[Mathias Parge]

Hello,

in the ChartControl-Help I found this hint to increase charting performace:

Simplify the chart item ControlTemplate - e.g. the Line item template contains by default an item label and a point mark visual. The point mark visual can be removed (as they are relatively insignificant when rendering thousands of records). With lots of points the sheer number of UI elements simply bogs the system down as discussed above). So if you cannot reduce the data points, you will need to simplify the chart item ControlTemplate.

Can anybody give me an example how to do this?

[Velin]

Hello Mathias Parge,

Here is how you can apply a new Line template that does not contain point marks:

xmlns:telerikCharting="clr-namespace:Telerik.Windows.Controls.Charting;assembly=Telerik.Windows.Controls.Charting"

<Style x:Key="LineStyle" TargetType="telerikCharting:Line">
                <Setter Property="Template" >
                    <Setter.Value>
                        <ControlTemplate TargetType="telerikCharting:Line">
                            <Canvas>
                                <Line x:Name="PART_LineGeometry"
                              Fill="Transparent"
                              Stroke="Transparent"
                              X1="0"
                              Y1="{TemplateBinding StartPointY}"
                              X2="{TemplateBinding EndPointX}"
                              Y2="{TemplateBinding EndPointY}"
                              Style="{TemplateBinding ItemStyle}" />
                            </Canvas>
                        </ControlTemplate>
                    </Setter.Value>
                </Setter>
            </Style>

ISeriesDefinition def = new LineSeriesDefinition() { ItemStyle = this.LayoutRoot.Resources["LineStyle"] as Style };

Hope this will help.

Greetings,
Velin
the Telerik team

Do you want to have your say when we set our development plans? Do you want to know when a feature you care about is added or when a bug fixed? Explore the Telerik Public Issue Tracking system and vote to affect the priority of the items.

[Earnest]

I'm using this method, seems to work but I have the following results where it appears the "EndPointX" value seems to be calculated incorrectly when plotting. I would expect that EndPointX would be the same value as StartPointX for the next segment. I have attached an image of the results I am seeing and the style below, I modified it to show a red stroke so I could visualize the style. Notice the red lines do not overlay the drawn waveform. Interestingly, at some zoom and scroll settings they do align. Is there a way to fix this?

<Style
            x:Key="LineStyle"
            TargetType="telerik:Line">
            <Setter
                Property="Template">
                <Setter.Value>
                    <ControlTemplate
                        TargetType="telerik:Line">
                        <Canvas>
                            <Line
                                x:Name="PART_LineGeometry"
                                Fill="Transparent"
                                Stroke="Red"
                                StrokeThickness="3"
                                X1="0"
                                Y1="{TemplateBinding StartPointY}"
                                X2="{TemplateBinding EndPointX}"
                                Y2="{TemplateBinding EndPointY}"
                                Style="{TemplateBinding ItemStyle}" />
                        </Canvas>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>

[Lauren]

Earnest, Thanks for the link.

I created the LineStyle in my App.xaml.
WITHOUT applying it to any chart, i get the following exception "Unable to cast object of type 'System.Windows.Style' to type 'System.Collections.Generic.IList`1[System.Windows.Style]'." when doing chart.Rebind().

I then removed all the chart.Rebind(), and applied the style to one of my chart. When zooming on that chart, i get the same exception.

Any idea about what's happening ?

Thanks for your help.