在工作中经常会遇到需要将一组数据绘制成曲线图的情况，最简单的方法是将数据导入Excel，然后使用绘图功能手动生成曲线图。但是如果基础数据频繁更改，则手动创建图形可能会变得枯燥乏味。本篇将利用DynamicDataDisplay 在WPF 中动态模拟CPU 使用率图表，实现动态生成曲线图。
新建项目将DynamicDataDisplay.dll 加载到References 中，打开MainWindow.xaml 添加命名空间xmlns:d3="http://research.microsoft.com/DynamicDataDisplay/1.0"。通过<d3:ChartPlotter> 创建一个图表框架，在其中添加两条整型坐标轴，X轴：<d3:HorizontalIntegerAxis>，Y轴：<d3:VerticalIntegerAxis>。<d3:Header> 用来设置图表名称，<d3:VerticalAxisTitle> 用来设置Y轴名称。
<Window x:Class="WpfPerformance.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d3="http://research.microsoft.com/DynamicDataDisplay/1.0" Title="CPU Performance" Loaded="Window_Loaded" Height="350" W
idth="525"> <Grid> <Grid.RowDefinitions> <RowDefinition Height="Auto"/> <RowDefinition Height="*"/> </Grid.RowDefinitions> <StackPanel Orientation="Horizontal"> <TextBlock Text="CPU Usage" Margin="20,10,0,0" FontSize="15" FontWeight="Bold"/> <TextBlock x:Name="cpuUsageText" Margin="10,10,0,0" FontSize="15"/> </StackPanel> <d3:ChartPlotter x:Name="plotter" Margin="10,10,20,10" Grid.Row="1"> <d3:ChartPlotter.VerticalAxis> <d3:VerticalIntegerAxis /> </d3:ChartPlotter.VerticalAxis> <d3:ChartPlotter.HorizontalAxis> <d3:HorizontalIntegerAxis /> </d3:ChartPlotter.HorizontalAxis> <d3:Header Content="CPU Performance History"/> <d3:VerticalAxisTitle Content="Percentage"/> </d3:ChartPlotter> </Grid></Window>
接下来工作需要通过C#每秒获取一次CPU使用率，并将这些数据生成坐标点（Point）绘制在图表中。 以下是MainWindow.xaml.cs 部分的代码内容。
using System;using System.Diagnostics;using System.Windows;using System.Windows.Media;using System.Windows.Threading;using Microsoft.Research.DynamicDataDisplay;using Microsoft.Research.DynamicDataDisplay.DataSources;namespace WpfPerformance{ public partial class MainWindow : Window { private ObservableDataSource<Point> dataSource = new ObservableDataSource<Point>(); private PerformanceCounter cpuPerformance = new PerformanceCounter(); private DispatcherTimer timer = new DispatcherTimer(); private int i = 0; public MainWindow() { InitializeComponent(); } private void AnimatedPlot(object sender, EventArgs e) { cpuPerformance.CategoryName = "Processor"; cpuPerformance.CounterName = "% Processor Time"; cpuPerformance.InstanceName = "_Total"; double x = i; double y = cpuPerformance.NextValue(); Point point = new Point(x, y); dataSource.AppendAsync(base.Dispatcher, point); cpuUsageText.Text = String.Format("{0:0}%", y); i++; } private void Window_Loaded(object sender, RoutedEventArgs e) { plotter.AddLineGraph(dataSource, Colors.Green, 2, "Percentage"); timer.Interval = TimeSpan.FromSeconds(1); timer.Tick += new EventHandler(AnimatedPlot); timer.IsEnabled = true; plotter.Viewport.FitToView(); } }}
通过ObservableDataSource<Point> 动态存储图表坐标点，PerformanceCounter 获取CPU使用率数值，DispatcherTimer 计时器在规定间隔进行取数操作，整型i 作为CPU使用率坐标点的X轴数值。
private ObservableDataSource<Point> dataSource = new ObservableDataSource<Point>();private PerformanceCounter cpuPerformance = new PerformanceCounter();private DispatcherTimer timer = new DispatcherTimer();private int i = 0;
AnimatedPlot 事件用于构造坐标点，通过设置cpuPerformance 相关参数，并使用NextValue() 方法获取当前CPU使用率数据作为Y值，整型i 作为X值。将X、Y值构造为坐标点（Point），并通过异步方式存储在dataSource 中。
private void AnimatedPlot(object sender, EventArgs e){ cpuPerformance.CategoryName = "Processor"; cpuPerformance.CounterName = "% Processor Time"; cpuPerformance.InstanceName = "_Total"; double x = i; double y = cpuPerformance.NextValue(); Point point = new Point(x, y); dataSource.AppendAsync(base.Dispatcher, point); cpuUsageText.Text = String.Format("{0:0}%", y); i++;}
最后通过Window_Loaded 将事件加载到<Window> 中，AddLineGraph 方法将dataSource 中的坐标点绘制到图表中，曲线颜色定义为绿色，粗细设置为2，曲线名称为"Percentage"。设置计时器间隔为1秒，连续执行AnimatedPlot 事件实时绘制新坐标点。
private void Window_Loaded(object sender, RoutedEventArgs e){ plotter.AddLineGraph(dataSource, Colors.Green, 2, "Percentage"); timer.Interval = TimeSpan.FromSeconds(1); timer.Tick += new EventHandler(AnimatedPlot); timer.IsEnabled = true; plotter.Viewport.FitToView();}
鼠标右键可将图表拷贝到其他文档：
动态演示
鼠标左键拖动图表浏览任意位置曲线数据，鼠标中键可以缩放显示曲线图。
源代码下载
WpfPerformance.zip