dashboard-devexpress-dot-dashboardcommon-c412a8d9.md
Calculates data points that are used to draw a custom trend indicator in the Chart dashboard item.
Namespace : DevExpress.DashboardCommon
Assembly : DevExpress.Dashboard.v25.2.Core.dll
NuGet Package : DevExpress.Dashboard.Core
public delegate Dictionary<AxisPoint, object> ChartIndicatorCalculateFunction(
Dictionary<AxisPoint, decimal?> points
);
Public Delegate Function ChartIndicatorCalculateFunction(
points As Dictionary(Of AxisPoint, Decimal?)
) As Dictionary(Of AxisPoint, Object)
| Name | Type | Description |
|---|---|---|
| points | Dictionary<AxisPoint, Nullable<Decimal>> |
A collection of axis data points in the Chart dashboard item.
|
| Type | Description |
|---|---|
| Dictionary<AxisPoint, Object> |
A collection of resulting data points that are used to draw the indicator.
|
The following example shows how to create a custom “Moving Average” indicator for a chart dashboard item:
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 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.
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:
ValueSpecifies 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:
NameSpecifies the name of the trend indicator within the indicators collection.ValueLevelGets or sets the value that specifies which series point value should be used to calculate the indicator.ShowInLegendSpecifies whether to display the trend indicator in the legend.LegendTextSpecifies the text that identifies the trend indicator within the legend.ThicknessSpecifies the thickness of the indicator line.ColorSpecifies the trend indicator’s color.DashStyleSpecifies the dash style used to paint the line.VisibleSpecifies 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;
}
}
}
Imports System
Imports System.Collections.Generic
Imports System.Drawing
Imports System.Linq
Imports System.Windows.Forms
Imports DevExpress.DashboardCommon
Imports DevExpress.DashboardCommon.ViewerData
Namespace WinForm
Partial Public Class FormDesigner
Inherits Form
Public Sub New()
Try
IndicatorFactory.Register(Of MovingIndicator)("Moving average")
Catch e As Exception
MessageBox.Show(e.Message)
End Try
InitializeComponent()
Dim dashboard = New Dashboard1()
Dim chartItem As ChartDashboardItem = TryCast(dashboard.Items.First(Function(x) x.ComponentName = "chartDashboardItem1"), ChartDashboardItem)
Dim trendLine As New MovingIndicator() With {
.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()
End Sub
End Class
Public Class MovingIndicator
Inherits ChartCustomIndicator
Protected Overrides Function Calculate(ByVal values As Dictionary(Of AxisPoint, Decimal?)) As Dictionary(Of AxisPoint, Object)
Dim items = New Dictionary(Of AxisPoint, Object)(values.Count)
Dim sum = Decimal.Zero
Dim count = 0
For Each point As KeyValuePair(Of AxisPoint, Decimal?) In values
If count = 0 Then
items.Add(point.Key, Nothing)
Else
items.Add(point.Key, sum / count)
End If
sum += If(point.Value, 0)
count += 1
Next point
Return items
End Function
End Class
End Namespace
The following image illustrates the result:
View Example: Dashboard for ASP.NET Core - Custom Trend Indicator
See Also