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CustomDrawSeriesEventArgsBase.DisposeLegendMarkerImage Property

Gets or sets the value specifying whether e.DXLegendMarkerImage should be disposed when drawing is finished.

Namespace: DevExpress.XtraCharts

Assembly: DevExpress.XtraCharts.v24.1.dll

NuGet Package: DevExpress.Charts

Declaration

public bool DisposeLegendMarkerImage { get; set; }

Property Value

Type Description
Boolean

true, to dispose the legend marker image settings; otherwise, false.

Remarks

Use the DisposeLegendMarkerImage property to release all the resources allocated to the object assigned to the e.DXLegendMarkerImage property.

Examples

Create Custom Legend Radio Buttons to Control Visibility of a Chart Series

This example demonstrates how to show chart series (Point, Line, or Area) depending on the selection state of a custom radio button in the chart legend.

View Example

Custom Legend Item

Use the ChartControl.CustomDrawSeries event handler to create a custom appearance for radio buttons based on the color of a selected series. Handle the ChartControl.LegendItemChecked event and use e.CheckedElement and SeriesBase.CheckedInLegend proeprties to show (or hide) the chart series when you switch between radio buttons.

using DevExpress.Drawing;
using DevExpress.XtraCharts;
using System;
using System.Drawing;
using System.Windows.Forms;

namespace CustomCheckboxesInLegendViewAndBehavior {
    public partial class mainForm : Form {
        const int LegendRadioSide = 17;
        const int LegendRadioInnerPointBoundsSide = 8;
        const float LegendRadioWidth = 1.5f;
        bool initializationFlag = false;

        public mainForm() {
            InitializeComponent();
            chartControl.BeginInit(); {
                chartControl.LegendItemChecked += OnLegendItemChecked;
                chartControl.CustomDrawSeries += OnCustomDrawSeries;
                chartControl.Legend.UseCheckBoxes = true;
                chartControl.Series["Point"].CheckedInLegend = false;
                chartControl.Series["Line"].CheckedInLegend = true;
                chartControl.Series["Area"].CheckedInLegend = false;
            }
            chartControl.EndInit();
            initializationFlag = false;
        }

        void OnLegendItemChecked(object sender, LegendItemCheckedEventArgs e) {
            if (initializationFlag == true)
                return;
            initializationFlag = true; {
                Series checkedSeries = e.CheckedElement as Series;
                if (checkedSeries == null)
                    throw new Exception("Expected series only");
                foreach (Series series in chartControl.Series)
                    series.CheckedInLegend = false;
                checkedSeries.CheckedInLegend = true;
                chartControl.Titles[0].Text = checkedSeries.Name;
            }
            initializationFlag = false;
        }

        void OnCustomDrawSeries(object sender, CustomDrawSeriesEventArgs e) {
            DXBitmap bitmap = new DXBitmap(LegendRadioSide, LegendRadioSide);
            using (DXGraphics graphics = DXGraphics.FromImage(bitmap)) {
                graphics.SmoothingMode = DXSmoothingMode.HighQuality;
                Color seriesColor = GetSeriesColor(e.Series, chartControl);
                using (DXPen radioPen = new DXPen(seriesColor, LegendRadioWidth)) {
                    int radioRadius = LegendRadioSide - 3;
                    Rectangle radioRectangle = new Rectangle(1, 1, radioRadius, radioRadius);
                    graphics.DrawEllipse(radioPen, radioRectangle);
                }
                if (e.Series.CheckedInLegend) {
                    using (DXBrush brush = new DXSolidBrush(seriesColor)) {
                        int coord = (LegendRadioSide - LegendRadioInnerPointBoundsSide) / 2;
                        Rectangle filledEllipseBounds = new Rectangle(coord, coord,
                              LegendRadioInnerPointBoundsSide, LegendRadioInnerPointBoundsSide);
                        graphics.FillEllipse(brush, filledEllipseBounds);
                    }
                }
            }
            e.DisposeLegendMarkerImage = true;
            e.DXLegendMarkerImage = bitmap;
        }

        Color GetSeriesColor(Series series, ChartControl chartControl) {
            int seriesIndex = chartControl.Series.IndexOf(series);
            string paletteName = chartControl.PaletteName;
            Palette currentPalette = chartControl.PaletteRepository[paletteName];
            PaletteEntry paletteEntryAccordingToSeries = currentPalette[seriesIndex];
            Color result = paletteEntryAccordingToSeries.Color;
            return result;
        }
    }
}

Draw a Custom Legend Marker for a Series

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 DisposeLegendMarkerImage property.

Note

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See Also