Hide legend of WPF Toolkit chart with more than on

Question

I am trying to use charts from the WPF Toolkit (with LineSeries) and I don't want a legend at all. I need this since I have 10 such charts each with data from a different source and I would like to draw one legend for all 10, to save screen real estate.

By default the legend appears the moment you add a second LineSeries. Is there any way to prevent it from even appearing?

Thanks,

sprite.

Answer 1

I tried Quarermeister's approach but his has a reference to a "datavis" assembly in the TargetType attribute that I didn't have.

<chartingToolkit:Chart.LegendStyle>
    <Style TargetType="Control">
        <Setter Property="Width" Value="0" />
        <Setter Property="Height" Value="0" />
    </Style>
</chartingToolkit:Chart.LegendStyle>

I also had to add padding to the right side of the chart because without the legend, my x-axis interval labels were extending outside the chart area.

Answer 2

Much more sensible approach...

<charting:LineSeries.LegendItemStyle >
  <Style TargetType="{x:Type charting:LegendItem}">
     <Setter Property="Visibility" Value="Collapsed"/>
  </Style>
</charting:LineSeries.LegendItemStyle>

Worked better for me than setting values to 0... Cheers!

Answer 3

Attached Property for DRY, easy usage:

<charting:Chart helpers:ChartHelpers.IsLegendHidden="True" ...

public static class ChartHelpers
    {
        static ChartHelpers()
        {
            HideLegendStyle = new Style(typeof(Legend));
            HideLegendStyle.Setters.Add(new Setter(Legend.WidthProperty, 0.0));
            HideLegendStyle.Setters.Add(new Setter(Legend.HeightProperty, 0.0));
            HideLegendStyle.Setters.Add(new Setter(Legend.VisibilityProperty, Visibility.Collapsed));
        }

        /// <summary>Gets a <see cref="Style"/> to hide the legend.</summary>
        public static readonly Style HideLegendStyle;

        #region IsLegendHidden

        [Category("Common")]
        [AttachedPropertyBrowsableForType(typeof(Chart))]
        public static bool GetIsLegendHidden(Chart chart)
        {
            return (bool)chart.GetValue(IsLegendHiddenProperty);
        }
        public static void SetIsLegendHidden(Chart chart, bool value)
        {
            chart.SetValue(IsLegendHiddenProperty, value);
        }

        public static readonly DependencyProperty IsLegendHiddenProperty = 
            DependencyProperty.RegisterAttached(
                "IsLegendHidden",
                typeof(bool), // type
                typeof(ChartHelpers), // containing static class
                new PropertyMetadata(default(bool), OnIsLegendHiddenChanged)
                );

        private static void OnIsLegendHiddenChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            OnIsLegendHiddenChanged((Chart)d, (bool)e.NewValue);
        }
        private static void OnIsLegendHiddenChanged(Chart chart, bool isHidden)
        {
            if (isHidden)
            {
                chart.LegendStyle = HideLegendStyle;
            }
        }

        #endregion IsLegendHidden
    }

Answer 4

There doesn't seem to be an especially clean way. One simple approach is to set the Legend's Width to zero using LegendStyle:

<charting:Chart>
    <charting:Chart.LegendStyle>
        <Style TargetType="datavis:Legend">
            <Setter Property="Width" Value="0" />
        </Style>
    </charting:Chart.LegendStyle>

A more drastic approach is to replace the ControlTemplate with one that does not include a Legend:

<charting:Chart>
    <charting:Chart.Template>
        <ControlTemplate TargetType="{x:Type charting:Chart}">
            <Border Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Padding="{TemplateBinding Padding}">
                <Grid>
                    <Grid.RowDefinitions>
                        <RowDefinition Height="Auto" />
                        <RowDefinition Height="*" />
                    </Grid.RowDefinitions>
                    <datavis:Title Content="{TemplateBinding Title}" Style="{TemplateBinding TitleStyle}" />
                    <chartingprimitives:EdgePanel Name="ChartArea" Style="{TemplateBinding ChartAreaStyle}" Grid.Row="1" Margin="0,15,0,15">
                        <Grid Panel.ZIndex="-1" Style="{TemplateBinding PlotAreaStyle}" />
                        <Border Panel.ZIndex="10" BorderBrush="#FF919191" BorderThickness="1" />
                    </chartingprimitives:EdgePanel>
                </Grid>
            </Border>
        </ControlTemplate>
    </charting:Chart.Template>

Use following namespaces:

xmlns:charting="clr-namespace:System.Windows.Controls.DataVisualization.Charting;assembly=System.Windows.Controls.DataVisualization.Toolkit"
xmlns:datavis="clr-namespace:System.Windows.Controls.DataVisualization;assembly=System.Windows.Controls.DataVisualization.Toolkit"
xmlns:chartingprimitives="clr-namespace:System.Windows.Controls.DataVisualization.Charting.Primitives;assembly=System.Windows.Controls.DataVisualization.Toolkit"