mobilecontrols-devexpress-dot-xamarinforms-dot-charts-b7b3886d.md
An interface that should be implemented by a class that defines custom labels for a series (the SeriesBase class descendant object).
Namespace : DevExpress.XamarinForms.Charts
Assembly : DevExpress.XamarinForms.Charts.dll
NuGet Package : DevExpress.XamarinForms.Charts
public interface ISeriesLabelTextProvider
The following members return ISeriesLabelTextProvider objects:
Implement the ISeriesLabelTextProvider interface and its GetText method if you need series labels to display custom text strings based on the underlying data point values.
The GetText method receives an argument of a type specific to a series:
|
Series Type
|
GetText Argument Type
| | --- | --- | |
|
| |
Area, Bar, Line, Spline, Point, and Bubble
|
| |
Candlestick and Stock
|
| |
|
|
This example shows how to configure the pie series so that its labels display point values as thousands, millions or billions of dollars in the following way:
ISeriesLabelTextProvider interface.<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:dxc="http://schemas.devexpress.com/xamarin/2014/forms/charts"
x:Class="SeriesLabelTextProviderExample.MainPage">
<dxc:PieChartView x:Name="chart" />
</ContentPage>
using System;
using Xamarin.Forms;
using System.Globalization;
using System.Collections.Generic;
using DevExpress.XamarinForms.Charts;
namespace SeriesLabelTextProviderExample {
public partial class MainPage : ContentPage {
public MainPage() {
DevExpress.XamarinForms.Charts.Initializer.Init();
InitializeComponent();
PieChartView pieChart = chart;
PieSeries pieSeries = new PieSeries() {
Data = new PieSeriesDataAdapter() {
LabelDataMember = "Label",
ValueDataMember = "Value",
DataSource = new List<DataItem>() {
new DataItem() { Label = "AAA", Value = 1230000 },
new DataItem() { Label = "BBB", Value = 3330000 },
new DataItem() { Label = "CCC", Value = 2100000 },
}
},
Label = new PieSeriesLabel() {
Position = PieSeriesLabelPosition.Inside,
TextProvider = new LabelTextProvider(),
Style = new PieSeriesLabelStyle(){
TextStyle = new TextStyle(){
Size = 18
}
}
}
};
pieChart.Series.Add(pieSeries);
}
}
public class LabelTextProvider : ISeriesLabelTextProvider {
string ISeriesLabelTextProvider.GetText(SeriesLabelValuesBase values) {
if (values is PieSeriesLabelValues seriesValues) {
double v = seriesValues.Value;
if (v >= 1000000000 || v <= -1000000000)
return (v / 1000000000.0).ToString("$#.###B", CultureInfo.InvariantCulture);
else if (v >= 1000000 || v <= -1000000)
return (v / 1000000.0).ToString("$#.###M", CultureInfo.InvariantCulture);
else if (v >= 1000 || v <= -1000)
return (v / 1000.0).ToString("$#.###K", CultureInfo.InvariantCulture);
else
return v.ToString();
}
return String.Empty;
}
}
public class DataItem {
public string Label { get; set; }
public double Value { get; set; }
}
}
See Also