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V24.1

CustomDrawSeriesEventArgsBase.DXLegendMarkerImage Property

Gets or sets the image of the legend item marker of the series or series point that is currently being painted.

Namespace: DevExpress.XtraCharts

Assembly: DevExpress.XtraCharts.v24.1.dll

NuGet Package: DevExpress.Charts

Declaration

public DXImage DXLegendMarkerImage { get; set; }

Property Value

Type Description
DXImage

The image of the legend item marker.

Remarks

Use this property instead of e.LegendMarkerImage to specify an image of the legend item marker.

Example

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

View Example

Assign a custom legend marker to the e.LegendMarkerImage property. Set the e.DisposeLegendMarkerImage property to true to avoid memory leaks. To customize options used to draw the series, cast e.SeriesDrawOptions to the DrawOptions class descendant that stores draw options of the required series view type.

using CustomDrawingSample.Model;
using DevExpress.Drawing;
using DevExpress.XtraCharts;
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.IO;
using System.Linq;

namespace CustomDrawingSample {
    public partial class Form1 : DevExpress.XtraEditors.XtraForm {
        string trackedSeriesName;
        Dictionary<string, DXImage> photoCache = new Dictionary<string, DXImage>();

        #region #Constants
        const int borderSize = 5;
        const int scaledPhotoWidth = 48;
        const int scaledPhotoHeight = 51;
        // Width and height of scaled photo with border.
        const int totalWidth = 58;
        const int totalHeight = 61;

        // 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.CustomDrawSeries += OnCustomDrawSeries;
            chart.ObjectHotTracked += OnObjectHotTracked;
        }

        private void OnObjectHotTracked(object sender, HotTrackEventArgs e) {
            trackedSeriesName = e.HitInfo.InSeries ? ((Series)e.HitInfo.Series).Name : null;
        }

        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 #CustomDrawSeriesImplementation
        private void OnCustomDrawSeries(object sender, CustomDrawSeriesEventArgs e) {
            bool isSelected = e.Series.Name.Equals(trackedSeriesName);
            // Design a series marker image.
            DXBitmap image = new DXBitmap(totalWidth, totalHeight);
            using (DXGraphics graphics = DXGraphics.FromImage(image)) {
                using (var fillBrush = isSelected ? (DXBrush)new DXHatchBrush(DXHatchStyle.DarkDownwardDiagonal,
                                                                          e.LegendDrawOptions.Color,
                                                                          e.LegendDrawOptions.ActualColor2)
                                                  : (DXBrush)new DXSolidBrush(e.LegendDrawOptions.Color)) {
                    graphics.FillRectangle(fillBrush, totalRect);
                }
                DXImage photo;
                if (photoCache.TryGetValue(e.Series.Name, out photo))
                    graphics.DrawImage(photo, photoRect);
            }
            e.DXLegendMarkerImage = image;
            e.DisposeLegendMarkerImage = true;

            BarDrawOptions options = e.SeriesDrawOptions as BarDrawOptions;
            if (options != null && isSelected) {
                options.FillStyle.FillMode = DevExpress.XtraCharts.FillMode.Hatch;
                ((HatchFillOptions)options.FillStyle.Options).HatchStyle = HatchStyle.DarkDownwardDiagonal;
            }
        }
        #endregion
    }
}

The following code snippets (auto-collected from DevExpress Examples) contain references to the DXLegendMarkerImage 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.

See Also