CrosshairLabelElement.DXMarkerImage Property

Specifies the marker image of a crosshair cursor label when implementing custom draw in the crosshair cursor.

Namespace: DevExpress.XtraCharts

Assembly: DevExpress.XtraCharts.v23.2.dll

NuGet Package: DevExpress.Charts

Declaration

C#

public DXImage DXMarkerImage { get; set; }

VB.NET

Public Property DXMarkerImage As DXImage

Property Value

Type	Description
DXImage	A DXImage object to be used as the crosshair label item’s marker.

Remarks

Use this property instead of MarkerImage to specify a marker image of a crosshair cursor label.

Example: Draw a Custom Series Marker in the Crosshair

This example demonstrates how to use the ChartControl.CustomDrawCrosshair event to modify the legend markers of bar series.

View Example

To access crosshair element groups, use the CustomDrawCrosshairEventArgs.CrosshairElementGroups property. Elements are separated into several groups when crosshair labels are displayed for each pane.

Use the following properties to access crosshair elements and customize them:

CrosshairElementGroup.HeaderElement

Gets the settings of crosshair group header elements to customize their appearance.

CrosshairElementGroup.CrosshairElements

Gets the settings of crosshair elements (crosshair value lines, crosshair value labels, crosshair labels) to customize their appearance.

CrosshairElementBase.LabelElement

Returns the Crosshair Cursor‘s label element to change its settings when using the ChartControl.CustomDrawCrosshair event to modify the Crosshair’s appearance.

CrosshairElementBase.AxisLabelElement

Returns the Crosshair Cursor‘s axis label element to change its settings when using the ChartControl.CustomDrawCrosshair event to modify the Crosshair’s appearance.

CrosshairLabelElement.DXMarkerImage

Specifies the marker image of a crosshair cursor label when implementing custom draw in the crosshair cursor.

Form1.cs

using CustomDrawCrosshairSample.Model;
using DevExpress.Drawing;
using DevExpress.XtraCharts;
using System;
using System.Collections.Generic;
using System.Drawing;
using System.IO;
using System.Linq;

namespace CustomDrawCrosshairSample {
    public partial class Form1 : DevExpress.XtraEditors.XtraForm {
        Dictionary<string, DXImage> photoCache = new Dictionary<string, DXImage>();
        Dictionary<string, DXBitmap> bitmapCache = new Dictionary<string, DXBitmap>();
        #region #Constants
        const int borderSize = 2;
        const int scaledPhotoWidth = 32;
        const int scaledPhotoHeight = 34;
        // Width and height of scaled photo with border.
        const int totalWidth = 36;
        const int totalHeight = 38;

        // Rects required to create a custom legend series marker.
        static readonly Rectangle photoRect = new Rectangle(
                borderSize, borderSize,
                scaledPhotoWidth, scaledPhotoHeight);
        static readonly Rectangle totalRect = new Rectangle(
                0, 0,
                totalWidth, totalHeight);
        #endregion

        public Form1() {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e) {
            using (var context = new NwindDbContext()) {
                InitPhotoCache(context.Employees);
                chart.DataSource = context.Orders.ToList();
            }

            chart.SeriesDataMember = "Employee.FullName";
            chart.SeriesTemplate.ArgumentDataMember = "OrderDate";
            chart.SeriesTemplate.ValueDataMembers.AddRange("Freight");

            XYDiagram diagram = chart.Diagram as XYDiagram;
            if (diagram != null) {
                diagram.AxisX.DateTimeScaleOptions.AggregateFunction = AggregateFunction.Sum;
                diagram.AxisX.DateTimeScaleOptions.MeasureUnit = DateTimeMeasureUnit.Year;
            }

            chart.CustomDrawCrosshair += OnCustomDrawCrosshair;
        }

        void InitPhotoCache(IEnumerable<Employee> employees) {
            photoCache.Clear();
            foreach (var employee in employees) {
                using (MemoryStream stream = new MemoryStream(employee.Photo)) {
                    if (!photoCache.ContainsKey(employee.FullName))
                        photoCache.Add(employee.FullName, DXImage.FromStream(stream));
                }
            }
        }

        #region #CustomDrawCrosshairHandler
        private void OnCustomDrawCrosshair(object sender, CustomDrawCrosshairEventArgs e) {
            foreach (CrosshairElementGroup group in e.CrosshairElementGroups) {
                if (group.CrosshairElements[0] != null)
                    group.HeaderElement.Text = String.Format("Sales in {0:yyyy}", group.CrosshairElements[0].SeriesPoint.DateTimeArgument);
                foreach (CrosshairElement element in group.CrosshairElements) {
                    DXBitmap image;
                    if (!bitmapCache.TryGetValue(element.Series.Name, out image)) {
                        image = new DXBitmap(totalWidth, totalHeight);
                        using (DXGraphics graphics = DXGraphics.FromImage(image)) {
                            using (DXSolidBrush brush = new DXSolidBrush(element.LabelElement.MarkerColor)) {
                                graphics.FillRectangle(brush, totalRect);
                            }
                            DXImage photo;
                            if (photoCache.TryGetValue(element.Series.Name, out photo))
                                graphics.DrawImage(photo, photoRect);
                        }
                        bitmapCache.Add(element.Series.Name, image);
                    }
                    element.LabelElement.DXMarkerImage = image;
                    element.LabelElement.MarkerSize = new Size(totalWidth, totalHeight);
                }
            }
        }
        #endregion 
    }
}

Form1.vb

Imports CustomDrawCrosshairSample.Model
Imports DevExpress.Drawing
Imports DevExpress.XtraCharts
Imports System
Imports System.Collections.Generic
Imports System.Drawing
Imports System.IO
Imports System.Linq

Namespace CustomDrawCrosshairSample

    Public Partial Class Form1
        Inherits DevExpress.XtraEditors.XtraForm

        Private photoCache As Dictionary(Of String, DXImage) = New Dictionary(Of String, DXImage)()

        Private bitmapCache As Dictionary(Of String, DXBitmap) = New Dictionary(Of String, DXBitmap)()

#Region "#Constants"
        Const borderSize As Integer = 2

        Const scaledPhotoWidth As Integer = 32

        Const scaledPhotoHeight As Integer = 34

        ' Width and height of scaled photo with border.
        Const totalWidth As Integer = 36

        Const totalHeight As Integer = 38

        ' Rects required to create a custom legend series marker.
        Private Shared ReadOnly photoRect As Rectangle = New Rectangle(borderSize, borderSize, scaledPhotoWidth, scaledPhotoHeight)

        Private Shared ReadOnly totalRect As Rectangle = New Rectangle(0, 0, totalWidth, totalHeight)

#End Region
        Public Sub New()
            InitializeComponent()
        End Sub

        Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs)
            Using context = New NwindDbContext()
                InitPhotoCache(context.Employees)
                chart.DataSource = context.Orders.ToList()
            End Using

            chart.SeriesDataMember = "Employee.FullName"
            chart.SeriesTemplate.ArgumentDataMember = "OrderDate"
            chart.SeriesTemplate.ValueDataMembers.AddRange("Freight")
            Dim diagram As XYDiagram = TryCast(chart.Diagram, XYDiagram)
            If diagram IsNot Nothing Then
                diagram.AxisX.DateTimeScaleOptions.AggregateFunction = AggregateFunction.Sum
                diagram.AxisX.DateTimeScaleOptions.MeasureUnit = DateTimeMeasureUnit.Year
            End If

            AddHandler chart.CustomDrawCrosshair, AddressOf OnCustomDrawCrosshair
        End Sub

        Private Sub InitPhotoCache(ByVal employees As IEnumerable(Of Employee))
            photoCache.Clear()
            For Each employee In employees
                Using stream As MemoryStream = New MemoryStream(employee.Photo)
                    If Not photoCache.ContainsKey(employee.FullName) Then photoCache.Add(employee.FullName, DXImage.FromStream(stream))
                End Using
            Next
        End Sub

#Region "#CustomDrawCrosshairHandler"
        Private Sub OnCustomDrawCrosshair(ByVal sender As Object, ByVal e As CustomDrawCrosshairEventArgs)
            For Each group As CrosshairElementGroup In e.CrosshairElementGroups
                If group.CrosshairElements(0) IsNot Nothing Then group.HeaderElement.Text = String.Format("Sales in {0:yyyy}", group.CrosshairElements(0).SeriesPoint.DateTimeArgument)
                For Each element As CrosshairElement In group.CrosshairElements
                    Dim image As DXBitmap
                    If Not bitmapCache.TryGetValue(element.Series.Name, image) Then
                        image = New DXBitmap(totalWidth, totalHeight)
                        Using graphics As DXGraphics = DXGraphics.FromImage(image)
                            Using brush As DXSolidBrush = New DXSolidBrush(element.LabelElement.MarkerColor)
                                graphics.FillRectangle(brush, totalRect)
                            End Using

                            Dim photo As DXImage
                            If photoCache.TryGetValue(element.Series.Name, photo) Then graphics.DrawImage(photo, photoRect)
                        End Using

                        bitmapCache.Add(element.Series.Name, image)
                    End If

                    element.LabelElement.DXMarkerImage = image
                    element.LabelElement.MarkerSize = New Size(totalWidth, totalHeight)
                Next
            Next
        End Sub
#End Region
    End Class
End Namespace

Related GitHub Examples

The following code snippet (auto-collected from DevExpress Examples) contains a reference to the DXMarkerImage property.

Note

The algorithm used to collect these code examples remains a work in progress. Accordingly, the links and snippets below may produce inaccurate results. If you encounter an issue with code examples below, please use the feedback form on this page to report the issue.

C#

winforms-chart-draw-a-custom-series-marker-in-the-crosshair/CS/CustomDrawCrosshairSample/Form1.cs#L83

}
element.LabelElement.DXMarkerImage = image;
element.LabelElement.MarkerSize = new Size(totalWidth, totalHeight);

VB.NET

winforms-chart-draw-a-custom-series-marker-in-the-crosshair/VB/CustomDrawCrosshairSample/Form1.vb#L88

element.LabelElement.DXMarkerImage = image
element.LabelElement.MarkerSize = New Size(totalWidth, totalHeight)