How to: Custom Draw a Crosshair Cursor

  • 3 minutes to read

This example shows how to provide a custom appearance for the crosshair cursor using the ChartControl.CustomDrawCrosshair event. This event is invoked when you click the Custom Draw Crosshair Cursor button on the form.

If you wish to display crosshair axis lines and labels on a chart before custom drawing the crosshair cursor, set the CrosshairOptions.ShowArgumentLabels, CrosshairOptions.ShowArgumentLine, CrosshairOptions.ShowValueLabels and CrosshairOptionsBase.ShowValueLine properties to true.

Note that the customization of the crosshair cursor is provided for the CrosshairOptions.SnapMode property set to NearestArgument.

View Example

<Window x:Class="CrosshairCustomDraw.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525" xmlns:dxc="http://schemas.devexpress.com/winfx/2008/xaml/charts">
    <Grid>
        <StackPanel>
            <dxc:ChartControl Height="269"  Name="chartControl1" CustomDrawCrosshair="chartControl1_CustomDrawCrosshair">
                <dxc:ChartControl.CrosshairOptions>
                    <dxc:CrosshairOptions ShowArgumentLabels="True" ShowArgumentLine="True" 
                        ShowValueLabels="True" ShowValueLine="True"/>
                </dxc:ChartControl.CrosshairOptions>
                <dxc:XYDiagram2D>
                <dxc:LineSeries2D DisplayName="Series1">
                    <dxc:SeriesPoint Argument="1" Value="50"/>
                    <dxc:SeriesPoint Argument="2" Value="44"/>
                    <dxc:SeriesPoint Argument="3" Value="55"/>
                    <dxc:SeriesPoint Argument="4" Value="77"/>
                </dxc:LineSeries2D>
                <dxc:LineSeries2D DisplayName="Series2">
                    <dxc:SeriesPoint Argument="1" Value="22"/>
                    <dxc:SeriesPoint Argument="2" Value="11"/>
                    <dxc:SeriesPoint Argument="3" Value="9"/>
                    <dxc:SeriesPoint Argument="4" Value="8"/>
                </dxc:LineSeries2D>
                </dxc:XYDiagram2D>
            </dxc:ChartControl>
            <Button Height="35" Content="Custom Draw Crosshair Cursor" Click="Button_Click"></Button>
        </StackPanel>
    </Grid>
</Window>
using System.Windows;
using DevExpress.Xpf.Charts;
using System.Windows.Media;


namespace CrosshairCustomDraw {
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window {
        bool handleCustomDraw;
        public MainWindow() {
            InitializeComponent();

        }

        private void Button_Click(object sender, RoutedEventArgs e) {
            handleCustomDraw = true;
            chartControl1.CustomDrawCrosshair += chartControl1_CustomDrawCrosshair;
        }

        private void chartControl1_CustomDrawCrosshair(object sender, CustomDrawCrosshairEventArgs e) {

            if (!handleCustomDraw) return;

            // Specify the crosshair argument line color, dash style and thickness.
            e.CrosshairLineElement.Brush = Brushes.Aqua;
            e.CrosshairLineElement.LineStyle.DashStyle = DashStyles.DashDot;
            e.CrosshairLineElement.LineStyle.Thickness = 3;

            // Specify  the back color for crosshair argument label. 
            foreach (CrosshairAxisLabelElement axisLabelElement in e.CrosshairAxisLabelElements)
                axisLabelElement.Background = Brushes.Blue;

            foreach (CrosshairElementGroup group in e.CrosshairElementGroups) {
                CrosshairElement element = group.CrosshairElements[0];

                // Specify the color, dash style and thickness for the crosshair value lines. 
                element.LineElement.Brush = Brushes.DarkViolet;
                element.LineElement.LineStyle.DashStyle = DashStyles.Dash;
                element.LineElement.LineStyle.Thickness = 2;

                // Specify the  font size and background for the crosshair value labels.
                element.AxisLabelElement.FontSize = 14;
                element.AxisLabelElement.Background = Brushes.Red;

                // Specify the foreground and  font size for the crosshair  cursor label that shows series. 
                element.LabelElement.Foreground = Brushes.Green;
                element.LabelElement.FontSize = 14;
            }

            foreach (CrosshairElementGroup group in e.CrosshairElementGroups) {
                CrosshairGroupHeaderElement groupHeaderElement = group.HeaderElement;

                // Specify the text, text color and font for the crosshair group header element. 
                groupHeaderElement.Text = "Custom draw";
                groupHeaderElement.Foreground = Brushes.Red;
                groupHeaderElement.FontSize = 15;
            }
        }
    }
}