WPF编程，Live Charts使用说明（43）——突出显示状态点

此示例在其值大于200时突出显示一个点，它使用线系列，但是库中的所有系列都支持此功能。

后台：

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using LiveCharts;
using LiveCharts.Configurations;
using LiveCharts.Defaults;
 
namespace Wpf.CartesianChart.PointState
{
    /// <summary>
    /// Interaction logic for PointStateExample.xaml
    /// </summary>
    public partial class PointStateExample : UserControl
    {
        public PointStateExample()
        {
            InitializeComponent();
            
            var r = new Random();
            Values = new ChartValues<ObservableValue>
            {
                new ObservableValue(r.Next(10, 400)),
                new ObservableValue(r.Next(10, 400)),
                new ObservableValue(r.Next(10, 400)),
                new ObservableValue(r.Next(10, 400)),
                new ObservableValue(r.Next(10, 400)),
                new ObservableValue(r.Next(10, 400))
            };
 
            //Lets define a custom mapper, to set fill and stroke
            //according to chart values...
            Mapper = Mappers.Xy<ObservableValue>()
                .X((item, index) => index)
                .Y(item => item.Value)
                .Fill(item => item.Value > 200 ? DangerBrush : null)
                .Stroke(item => item.Value > 200 ? DangerBrush : null);
 
            Formatter = x => x + " ms";
 
            DangerBrush = new SolidColorBrush(Color.FromRgb(238,83,80));
 
            DataContext = this;
        }
 
        public Func<double, string> Formatter { get; set; }
        public ChartValues<ObservableValue> Values { get; set; }
        public Brush DangerBrush { get; set; }
        public CartesianMapper<ObservableValue> Mapper { get; set; } 
 
        private void UpdateDataOnClick(object sender, RoutedEventArgs e)
        {
            var r = new Random();
            foreach (var observable in Values)
            {
                observable.Value = r.Next(10, 400);
            }
        }
    }
}

前台：

<UserControl x:Class="Wpf.CartesianChart.PointState.PointStateExample"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
             xmlns:lvc="clr-namespace:LiveCharts.Wpf;assembly=LiveCharts.Wpf"
             xmlns:pointState="clr-namespace:Wpf.CartesianChart.PointState"
             mc:Ignorable="d" 
             d:DesignHeight="300" d:DesignWidth="300" d:DataContext="{d:DesignInstance pointState:PointStateExample}">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition Height="*"></RowDefinition>
        </Grid.RowDefinitions>
        <Button Grid.Row="0" Click="UpdateDataOnClick">Update Data</Button>
        <lvc:CartesianChart Grid.Row="1">
            <lvc:CartesianChart.Series>
                <lvc:LineSeries Values="{Binding Values}" 
                                PointGeometrySize="20" 
                                PointForeground="White"
                                Configuration="{Binding Mapper}"/>
            </lvc:CartesianChart.Series>
        </lvc:CartesianChart>
    </Grid>
</UserControl>