CustomDrawCrosshairEventArgs.CrosshairElementGroups Property

Provides access to the settings of crosshair elements and crosshair group header elements to customize their appearance.

Namespace: DevExpress.XtraCharts

Assembly: DevExpress.XtraCharts.v20.2.dll

Declaration

public IList<CrosshairElementGroup> CrosshairElementGroups { get; }
Public ReadOnly Property CrosshairElementGroups As IList(Of CrosshairElementGroup)

Property Value

Type Description
IList<CrosshairElementGroup>

An object implementing the System.Collections.IList interface that represents the CrosshairElementGroup collection.

Remarks

Use the CrosshairElementGroups property to get access to the settings of a crosshair element group when handling the ChartControl.CustomDrawCrosshair event. After that, you can access the appearance settings of crosshair elements using the CrosshairElementGroup.CrosshairElements property and crosshair group header elements using the CrosshairElementGroup.HeaderElement property.

Examples

This example shows how to use the ChartControl.CustomDrawCrosshair event to provide a custom appearance for the crosshair cursor. This event is invoked when you select the Custom Draw Crosshair Cursor check box.

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

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

using System;
using System.Drawing;
using System.Windows.Forms;
using DevExpress.XtraCharts;

namespace CustomDrawCrosshairCursor {
    public partial class Form1 : Form {
        public Form1() {
            InitializeComponent();
        }
        private void OnCheckEditCheckedChanged(object sender, EventArgs e) {
            if (checkEdit1.Checked)
                chartControl1.CustomDrawCrosshair += OnChartControlCustomDrawCrosshair;
            else 
                chartControl1.CustomDrawCrosshair -= OnChartControlCustomDrawCrosshair;               
        }

        private void OnChartControlCustomDrawCrosshair(object sender, CustomDrawCrosshairEventArgs e) {
            // Specify the crosshair argument line color, dash style and thickness.
            e.CrosshairLineElement.Color = Color.Green;
            e.CrosshairLineElement.LineStyle.DashStyle = DashStyle.DashDot;
            e.CrosshairLineElement.LineStyle.Thickness = 3;

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

            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.TextColor = Color.Green;
                groupHeaderElement.Font = new Font(this.Font, FontStyle.Bold);

                // Obtain a crosshair element for the first series.
                CrosshairElement element = group.CrosshairElements[0];

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

                // Specify the text color and back color for the crosshair value labels.
                element.AxisLabelElement.TextColor = Color.Red;
                element.AxisLabelElement.BackColor = Color.Yellow;

                // Format the text shown for the series in the crosshair cursor label. Specify the text color and marker size. 
                element.LabelElement.TextColor = Color.Red;
                element.LabelElement.MarkerSize = new Size(15, 15);
                element.LabelElement.Text = string.Format("{0}: A={1}; V={2}", element.Series.Name, element.SeriesPoint.Argument, element.SeriesPoint.Values[0]);
            }
        }
    }
}
See Also