How to: Custom Draw Series Points
- 5 minutes to read
This example demonstrates how to use the ChartControl.CustomDrawSeriesPoint event to modify the legend markers of nested donut series points.
Assign a custom legend marker to the e.DXLegendMarkerImage property. Set the e.DisposeLegendMarkerImage property to true to avoid memory leaks. To customize options used to draw the series point, cast e.SeriesDrawOptions to the DrawOptions class descendant that stores draw options of the required series view type.
using CustomSeriesPointDrawingSample.Model;
using DevExpress.Drawing;
using DevExpress.XtraCharts;
using System;
using System.Collections.Generic;
using System.Data;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.IO;
using System.Linq;
using System.Windows.Forms;
namespace CustomSeriesPointDrawingSample {
public partial class Form1 : Form {
object trackedPointArgument;
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();
}
#region #ChartPreparation
private void Form1_Load(object sender, EventArgs e) {
chart.CustomDrawSeriesPoint += OnCustomDrawSeriesPoint;
chart.BoundDataChanged += OnBoundDataChanged;
chart.ObjectHotTracked += OnObjectHotTracked;
using (var context = new NwindDbContext()) {
chart.DataSource = PrepareDataSource(context.Orders);
InitPhotoCache(context.Employees);
}
chart.SeriesDataMember = "Year";
chart.SeriesTemplate.ArgumentDataMember = "Employee";
chart.SeriesTemplate.ValueDataMembers.AddRange("Value");
chart.SeriesTemplate.ToolTipPointPattern = "{S}: {A} ({VP:P})";
chart.SeriesTemplate.SeriesPointsSorting = SortingMode.Ascending;
}
#endregion
#region #AutogeneratedSeriesModifying
private void OnBoundDataChanged(object sender, EventArgs e) {
if (chart.Series.Count <= 1) return;
for (int i = 1; i < chart.Series.Count; ++i)
chart.Series[i].ShowInLegend = false;
}
#endregion
#region #CustomPointDrawing
private void OnCustomDrawSeriesPoint(object sender, CustomDrawSeriesPointEventArgs e) {
// Design a series marker image.
DXBitmap image = new DXBitmap(totalWidth, totalHeight);
bool isSelected = trackedPointArgument != null && e.SeriesPoint.Argument.Equals(trackedPointArgument);
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.SeriesPoint.Argument, out photo))
graphics.DrawImage(photo, photoRect);
}
e.DXLegendMarkerImage = image;
e.DisposeLegendMarkerImage = true;
PieDrawOptions options = e.SeriesDrawOptions as PieDrawOptions;
if (isSelected && options != null) {
options.FillStyle.FillMode = DevExpress.XtraCharts.FillMode.Hatch;
((HatchFillOptions)options.FillStyle.Options).HatchStyle = HatchStyle.DarkDownwardDiagonal;
}
}
#endregion
private void OnObjectHotTracked(object sender, HotTrackEventArgs e) {
trackedPointArgument = e.HitInfo.InSeriesPoint ? e.HitInfo.SeriesPoint.Argument : null;
chart.Invalidate();
}
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));
}
}
}
List<SalesPoint> PrepareDataSource(IEnumerable<Order> orders) {
var query = from o in orders
group o by new {
Year = o.OrderDate.Year,
Employee = o.Employee.FirstName + " " + o.Employee.LastName
}
into g
select new {
Employee = g.Key.Employee,
Year = g.Key.Year,
Values = g.Select(o => o.Freight.HasValue ? o.Freight.Value : 0)
};
List<SalesPoint> points = new List<SalesPoint>();
foreach (var item in query) {
points.Add(new SalesPoint {
Employee = item.Employee,
Year = item.Year,
Value = item.Values.Aggregate((d1, d2) => d1 + d2)
});
}
return points;
}
}
}
class SalesPoint {
public string Employee { get; set; }
public int Year { get; set; }
public decimal Value { get; set; }
}
See Also