CrosshairElementGroup.HeaderElement Property
Gets the settings of crosshair group header elements to customize their appearance.
Namespace: DevExpress.XtraCharts
Assembly: DevExpress.XtraCharts.v18.2.dll
Declaration
Property Value
Type | Description |
---|---|
CrosshairGroupHeaderElement | An object implementing the System.Collections.IEnumerable interface that represents the CrosshairGroupHeaderElement collection. |
Remarks
Use the HeaderElement property to get access to the appearance settings of the crosshair group header elements when implementing the ChartControl.CustomDrawCrosshair event.
To learn more about a crosshair cursor, see Tooltip and Crosshair Cursor.
Example
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.ShowArgumentLine, CrosshairOptions.ShowArgumentLabels, CrosshairOptions.ShowValueLabels and CrosshairOptions.ShowValueLine properties to true.
Note that the customization of the crosshair cursor is provided for the CrosshairOptions.SnapMode property set to NearestArgument.
Note
A complete sample project is available at https://github.com/DevExpress-Examples/how-to-custom-draw-a-crosshair-cursor-e4307
using System;
using System.Drawing;
using System.Windows.Forms;
using DevExpress.XtraCharts;
namespace CustomDrawCrosshairCursor {
public partial class Form1 : Form {
bool handleCustomDraw;
public Form1() {
InitializeComponent();
}
private void button1_Click(object sender, EventArgs 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.Color = Color.Green;
e.CrosshairLineElement.LineStyle.DashStyle = DashStyle.DashDot;
e.CrosshairLineElement.LineStyle.Thickness = 3;
// Specify the back color for crosshair argument label.
foreach (CrosshairAxisLabelElement axisLabelElement in e.CrosshairAxisLabelElements)
axisLabelElement.BackColor = Color.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.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;
// Specify the text color and marker size for the crosshair cursor label that shows series.
element.LabelElement.TextColor = Color.Red;
element.LabelElement.MarkerSize = new Size(15, 15);
}
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);
}
}
}
}