CrosshairGroupHeaderElement Class

Defines the appearance of the crosshair group header element when custom drawing a crosshair cursor using the ChartControl.CustomDrawCrosshair event.

Namespace: DevExpress.XtraCharts

Assembly: DevExpress.XtraCharts.v19.2.dll

Declaration

C#

public class CrosshairGroupHeaderElement :
    BaseCrosshairLabelElement

VB.NET

Public Class CrosshairGroupHeaderElement
    Inherits BaseCrosshairLabelElement

Related API Members

The following members return CrosshairGroupHeaderElement objects:

• CrosshairElementGroup.HeaderElement

Remarks

To access the appearance properties of the CrosshairGroupHeaderElement object , use the CustomDrawCrosshairEventArgs.CrosshairGroupHeaderElements property when custom drawing a crosshair cursor using the ChartControl.CustomDrawCrosshair event handler.

For more information on crosshair cursors, see Tooltip and Crosshair Cursor.

Example

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.

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 {
        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]);
            }
        }
    }
}

Form1.vb

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

Namespace CustomDrawCrosshairCursor
    Public Partial Class Form1
        Inherits Form

        Public Sub New()
            InitializeComponent
        End Sub

        Private Sub OnCheckEditCheckedChanged(ByVal sender As Object, ByVal e As EventArgs)
            If checkEdit1.Checked Then
                chartControl1.CustomDrawCrosshair += AddressOf OnChartControlCustomDrawCrosshair
            Else
                chartControl1.CustomDrawCrosshair -= AddressOf OnChartControlCustomDrawCrosshair
            End If
        End Sub

        Private Sub OnChartControlCustomDrawCrosshair(ByVal sender As Object, ByVal e As CustomDrawCrosshairEventArgs)
            ' 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.
            For Each axisLabelElement As CrosshairAxisLabelElement In e.CrosshairAxisLabelElements
                axisLabelElement.BackColor = Color.Blue
            Next

            ' Specify the text, text color and font for the crosshair group header element.
            For Each group As CrosshairElementGroup In e.CrosshairElementGroups
                Dim groupHeaderElement As CrosshairGroupHeaderElement = group.HeaderElement
                groupHeaderElement.Text = "Custom draw"
                groupHeaderElement.TextColor = Color.Green
                groupHeaderElement.Font = New Font(Me.Font, FontStyle.Bold)

                ' Obtain a crosshair element for the first series.
                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

                ' 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))
            Next
        End Sub
    End Class
End Namespace

Inheritance

Object

BaseCrosshairLabelElement

CrosshairGroupHeaderElement