Annotation questions

[Mike]

Hi, I am attempting to add a custom line or custom grid line annotation to my RadChart. I need to make the line dashed, but do so completely in c#, not using any XAML styles. How would I do this?

Also, how would I add my annotation to my legend, completely in code. I saw the example:
http://www.telerik.com/help/wpf/radchart-how-to-add-annotations-in-chart-legend.html, but that uses XAML styles, and I can't do that.

How would I ensure that the annotation appears in front of the data series? I.E. the bars for the bar chart are behind the annotation.

And finally, how would I add labels to annotations, again, in c# code only.

[Petar Kirov]

Hello Mike,

Thanks for contacting us.

As you can see from the help topics here and here, you can add annotations in code-behind (C#) like this:

Style dashedLineStyle =
    new Style(typeof(System.Windows.Shapes.Line));
dashedLineStyle.Setters.Add(
    new Setter(System.Windows.Shapes.Line.StrokeDashArrayProperty, "1 2 3"));

this.RadChart1.DefaultView.ChartArea.Annotations.Add(
    new CustomGridLine
    {
        XIntercept = 7,
        Stroke = new SolidColorBrush(Colors.Blue),
        StrokeThickness = 2,
        ElementStyle = dashedLineStyle
    });

Style dashedLineStyle2 = new Style(typeof(System.Windows.Shapes.Line));
dashedLineStyle2.Setters.Add(
    new Setter(System.Windows.Shapes.Line.StrokeDashArrayProperty, "1 2 4 8"));

this.RadChart1.DefaultView.ChartArea.Annotations.Add(
    new CustomLine
    {

        MinX = 2,
        MinY = 2,
        MaxX = 5,
        MaxY = 10,
        Slope = 2.66,
        YIntercept = -3.32,
        Stroke = new SolidColorBrush(Colors.Red),
        StrokeThickness = 2,
        ElementStyle = dashedLineStyle2
    });

This is how you can convert a Style from XAML to C#: 
XAML:

<Style x:Key="customGridLineStyle" TargetType="Line">
    <Setter Property="StrokeDashArray" Value="1,1" />
</Style>

C#: 

Style customGridLineStyle = new Style();
customGridLineStyle.TargetType = typeof(System.Windows.Shapes.Line);
customGridLineStyle.Setters.Add(
    new Setter(System.Windows.Shapes.Line.StrokeDashArrayProperty, "1 1"));

When it comes to using it:
XAML:

<Window.Resources>
    <Style x:Key="customGridLineStyle" TargetType="Line">
        <Setter Property="StrokeDashArray" Value="1,1" />
    </Style>
</Window.Resources>

<Grid x:Name="LayoutRoot">
    <Line Style="{StaticResource customGridLineStyle}"/>

C#: 

Style customGridLineStyle = new Style();
customGridLineStyle.TargetType = typeof(System.Windows.Shapes.Line);
customGridLineStyle.Setters.Add(
    new Setter(System.Windows.Shapes.Line.StrokeDashArrayProperty, "1 1"));

var line = new System.Windows.Shapes.Line();
line.Style = customGridLineStyle;
this.LayoutRoot.Children.Add(line);

In theory anything written in XAML can be done in C#.

That said it is possible to rewrite the the Styles and templates from this article, however it would not be practical, will require a lot of effort and is out of the scope of Telerik Support. 

The only thing you need to get it running is to copy-paste everything that start with <Style ... to the <Window.Resources> of your xaml file and put the chart itself ( <telerik:RadChart ... ) in the LayoutRoot (typically the <Grid x:Name="LayoutRoot" ... )

I hope this helps.

Regards,
Petar Kirov
the Telerik team

[Mike]

Thank you for this. It makes sense. However, when I try to do this for a Telerik.Windows.Controls.Charting.CustomLine as follows:

Style customGridLineStyle = new Style();
customGridLineStyle.TargetType = typeof(System.Windows.Shapes.Line);
customGridLineStyle.Setters.Add(
          new Setter(System.Windows.Shapes.Line.StrokeDashArrayProperty, "1 1"));

customLine.ElementStyle = customGridLineStyle;

I get an error saying:

'1 1' is not a valid value for the 'System.Windows.Shapes.Shape.StrokeDashArray' property on a Setter.
Any ideas?

Also, is there any way to bring the annotation to the front of the chart instead of behind the chart series?

[Mike]

I have figured out the issue above. I solved it by setting the value of the property to a DoubleCollection.

DoubleCollection dc = new DoubleCollection();
dc.Add(1.0);
dc.Add(1.0);

Style customGridLineStyle = new Style();
customGridLineStyle.TargetType = typeof(System.Windows.Shapes.Line);
customGridLineStyle.Setters.Add(
          new Setter(System.Windows.Shapes.Line.StrokeDashArrayProperty, dc));

My only remaining issue is bringing the annotation to the front of the chart series. Is this possible?

[Petar Kirov]

Hi Mike,

It seams that the problem comes from the framework. I initially tested this in Silverlight and the code I provided worked as expect, but setting the StrokeDashArray property as DoubleCollection didn't. 

By creating a sample SL and WPF projects containing only a Line and setting their style through code-behind you can reproduce this issue.

On second question - by default the layer that holds the annotations is behind the series. However you can change that by re-templating the ChartArea. This help topic describes exactly how. 
 
Kind regards,
Petar Kirov
the Telerik team