ChartIndicatorCalculateFunction Delegate
Calculates data points that are used to draw a custom trend indicator in the Chart dashboard item.
Namespace: DevExpress.DashboardCommon
Assembly: DevExpress.Dashboard.v24.2.Core.dll
Declaration
public delegate Dictionary<AxisPoint, object> ChartIndicatorCalculateFunction(
Dictionary<AxisPoint, decimal?> points
);
Parameters
Name | Type | Description |
---|---|---|
points | Dictionary<AxisPoint, Nullable<Decimal>> | A collection of axis data points in the Chart dashboard item. |
Returns
Type | Description |
---|---|
Dictionary<AxisPoint, Object> | A collection of resulting data points that are used to draw the indicator. |
Remarks
The following example shows how to create a custom “Moving Average” indicator for a chart dashboard item:
Create a Custom Indicator Type
Create a ChartCustomIndicator
descendant (the MovingIndicator
class in this example). MovingIndicator
accepts a collection of data points, evaluates the values, and returns the resulting points. These points are used to draw the indicator.
Register the Custom Indicator Type
Register the MovingIndicator
type in IndicatorFactory to make this type available as the indicator type in the Trend Indicators editor.
Call the Register
method in your application before you save and load a dashboard to serialize and deserialize the indicator within the dashboard XML.
Configure and Display the Indicator
Create an instance of MovingIndicator
and specify the indicator settings:
This property is required to display the indicator in the Chart dashboard item when you launch the application:
- Value
- Specifies the measure data item that is used to calculate the trend indicator.
If you do not specify the following properties, their default values are used:
- Name
- Specifies the name of the trend indicator within the indicators collection.
- ValueLevel
- Gets or sets the value that specifies which series point value should be used to calculate the indicator.
- ShowInLegend
- Specifies whether to display the trend indicator in the legend.
- LegendText
- Specifies the text that identifies the trend indicator within the legend.
- Thickness
- Specifies the thickness of the indicator line.
- Color
- Specifies the trend indicator’s color.
- DashStyle
- Specifies the dash style used to paint the line.
- Visible
- Specifies whether to display the trend indicator.
Add MovingIndicator
to the chart indicators collection to display the configured indicator in the UI.
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Windows.Forms;
using DevExpress.DashboardCommon;
using DevExpress.DashboardCommon.ViewerData;
namespace WinForm {
public partial class FormDesigner : Form {
public FormDesigner() {
try {
IndicatorFactory.Register<MovingIndicator>("Moving average");
} catch(Exception e) {
MessageBox.Show(e.Message);
}
InitializeComponent();
var dashboard = new Dashboard1();
ChartDashboardItem chartItem = dashboard.Items.First(x => x.ComponentName == "chartDashboardItem1") as ChartDashboardItem;
MovingIndicator trendLine = new MovingIndicator() {
Name = "MovingLine1",
Value = "DataItem1",
ValueLevel = DevExpress.XtraCharts.ValueLevel.Value,
Color = Color.Orange,
LegendText = "Moving Average"
};
chartItem.Indicators.Add(trendLine);
dashboardDesigner.Dashboard = dashboard;
dashboardDesigner.CreateRibbon();
dashboardDesigner.CreateCustomItemBars();
}
}
public class MovingIndicator : ChartCustomIndicator {
protected override Dictionary<AxisPoint, object> Calculate(Dictionary<AxisPoint, decimal?> values) {
var items = new Dictionary<AxisPoint, object>(values.Count);
var sum = decimal.Zero;
var count = 0;
foreach(KeyValuePair<AxisPoint, decimal?> point in values) {
if(count == 0) {
items.Add(point.Key, null);
} else {
items.Add(point.Key, sum / count);
}
sum += point.Value ?? 0;
count++;
}
return items;
}
}
}
The following image illustrates the result: