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

C#

public CrosshairGroupHeaderElement HeaderElement { get; }

VB.NET

Public ReadOnly Property HeaderElement As CrosshairGroupHeaderElement

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

Form1.cs

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);
            }
        }
    }
}

Form1.vb

Imports System
Imports System.Drawing
Imports System.Windows.Forms
Imports DevExpress.XtraCharts

Namespace CustomDrawCrosshairCursor
    Partial Public Class Form1
        Inherits Form

        Private handleCustomDraw As Boolean
        Public Sub New()
            InitializeComponent()
        End Sub

        Private Sub button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles button1.Click
            handleCustomDraw = True
            AddHandler chartControl1.CustomDrawCrosshair, AddressOf chartControl1_CustomDrawCrosshair
        End Sub

        Private Sub chartControl1_CustomDrawCrosshair(ByVal sender As Object, ByVal e As CustomDrawCrosshairEventArgs) Handles chartControl1.CustomDrawCrosshair
            If Not handleCustomDraw Then
                Return
            End If

            ' 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. 
            For Each axisLabelElement As CrosshairAxisLabelElement In e.CrosshairAxisLabelElements
                axisLabelElement.BackColor = Color.Blue
            Next axisLabelElement

            For Each group As CrosshairElementGroup In e.CrosshairElementGroups
                Dim element As CrosshairElement = 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)
            Next group

            For Each group As CrosshairElementGroup In e.CrosshairElementGroups
                Dim groupHeaderElement As CrosshairGroupHeaderElement = 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(Me.Font, FontStyle.Bold)
            Next group
        End Sub
    End Class
End Namespace