如何在WinForms C＃中使用LiveCharts库创建饼图

本文概述

1.安装LiveCharts
2.添加一个PieChart组件
3.在PieChart上显示数据
4.自定义PieChart

当你需要处理科学主题, 数据可视化(或最简单的为仪表盘创建图表)时, 饼图无疑是显示简单数据的最常用和最广为人知的方法之一。饼图用于显示某个值的总和的百分比, 因此所有切片(段)的总和必须为100％。如果你愿意在WinForms应用程序中显示此类图表, 建议你为此使用一个库, 而不是使用.NET的Drawing类进行绘制
在本文中, 我们将向你展示如何使用LiveCharts库在带有C＃的WinForms应用程序中显示饼图。
1.安装LiveCharts 要在Visual Studio中的项目上安装此软件包, 请转到解决方案资源管理器, 然后右键单击你的项目。从下拉列表中选择管理NuGet软件包选项：

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在管理器中, 转到浏览选项卡并搜索LiveCharts包：

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选择Beto Rodriguez的WinForms软件包并将其安装在你的项目中。安装完成后, 你将可以使用该库在代码上呈现图表。有关此库的更多信息, 请访问Github上的官方存储库。
2.添加一个PieChart组件在项目中安装LiveCharts库后, Visual Studio会自动添加一组新控件, 使你可以将图表添加到WinForms布局中。打开表单设计器时, 可以在Visual Studio的左侧找到它。为了开始本文的示例, 我们将添加一个PieChart项, 因此只需将其拖放到表单中即可：

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这将添加默认图像, 以让你知道该组件正在占用空间(数据没有意义)。默认情况下, 第一个项目在代码中将被命名为pieChart1, 但是你可以稍后更改组件的名称。在我们的示例中, 我们将保留第一个元素的相同名称。
3.在PieChart上显示数据现在你的表单以图形方式显示了一个PieChart, 你需要设置一些将要绘制的数据。首先, 你需要定义一个包含PieSeries元素的数据集合, 这些元素可以在SeriesCollection对象中进行动态或静态定义。每个PieSeries对象至少需要定义Title, LabelPoint和Values选项才能正确显示。可以使用ChartValues类的新实例及其类型和原始值来定义每个项目的值。
【如何在WinForms C＃中使用LiveCharts库创建饼图】可以根据需要在集合上添加数据, 也可以立即在SeriesCollection构造函数中对其进行定义：

// Include the required namespace of LiveChartsusing LiveCharts; using LiveCharts.Wpf; // It's important to run the code inside the load event of the form, so the component will be drawn after this correctlyprivate void Form1_Load(object sender, EventArgs e){// Define the label that will appear over the piece of the chart// in this case we'll show the given value and the percentage e.g 123 (8%)Func< ChartPoint, string> labelPoint = chartPoint => string.Format("{0} ({1:P})", chartPoint.Y, chartPoint.Participation); // Define a collection of items to display in the chart SeriesCollection piechartData = http://www.srcmini.com/new SeriesCollection{new PieSeries{Title ="First Item", Values = new ChartValues< double> {25}, DataLabels = true, LabelPoint = labelPoint}, new PieSeries{Title = "Second Item", Values = new ChartValues< double> {25}, DataLabels = true, LabelPoint = labelPoint}, new PieSeries{Title = "Third Item", Values = new ChartValues< double> {25}, DataLabels = true, LabelPoint = labelPoint}}; // You can add a new item dinamically with the add method of the collection// Useful when you define the data dinamically and not staticallypiechartData.Add(new PieSeries{Title = "Fourth Item", Values = new ChartValues< double> { 25 }, DataLabels = true, LabelPoint = labelPoint, Fill = System.Windows.Media.Brushes.Gray}); // Define the collection of Values to display in the Pie ChartpieChart1.Series = piechartData; // Set the legend location to appear in the Right side of the chartpieChart1.LegendLocation = LegendLocation.Right; }

如前所述, 代码需要在表单加载事件之后/期间执行。以下示例显示了文章开头显示的图形, 该图形显示了该国核弹头的数量和百分比：

using System; using System.Windows.Forms; // Include the required namespace of LiveChartsusing LiveCharts; using LiveCharts.Wpf; namespace Sandbox{public partial class Form1 : Form{public Form1(){InitializeComponent(); }private void Form1_Load(object sender, EventArgs e){// Define the label that will appear over the piece of the chart// in this case we'll show the given value and the percentage e.g 123 (8%)Func< ChartPoint, string> labelPoint = chartPoint => string.Format("{0} ({1:P})", chartPoint.Y, chartPoint.Participation); // Define the collection of Values to display in the Pie ChartpieChart1.Series = new SeriesCollection{new PieSeries{Title = "USA", Values = new ChartValues< double> {6450}, DataLabels = true, LabelPoint = labelPoint, }, new PieSeries{Title = "Russia", Values = new ChartValues< double> {6850}, DataLabels = true, LabelPoint = labelPoint}, new PieSeries{Title = "United Kingdom", Values = new ChartValues< double> {215}, DataLabels = true, LabelPoint = labelPoint}, new PieSeries{Title = "France", Values = new ChartValues< double> {300}, DataLabels = true, LabelPoint = labelPoint}, new PieSeries{Title = "China", Values = new ChartValues< double> {280}, DataLabels = true, LabelPoint = labelPoint}}; // Set the legend location to appear in the bottom of the chartpieChart1.LegendLocation = LegendLocation.Bottom; }}}

4.自定义PieChart 对于定制, 几乎每个人都需要的是基本功能。例如, 要更改颜色, 你需要定义System.Windows.Media.Brushes密封类的填充颜色：

new PieSeries{Title = "Second Item", Values = new ChartValues< double> {25}, DataLabels = true, LabelPoint = labelPoint, // Define the piece with a green colorFill = System.Windows.Media.Brushes.Green}

或者, 如果要突出显示饼图中的某段, 请使用PushOut选项：

new PieSeries{Title = "Second Item", Values = new ChartValues< double> {25}, DataLabels = true, LabelPoint = labelPoint, // Highligh this piece of the chartPushOut = 15, }

如下代码：

// Define the label that will appear over the piece of the chart// in this case we'll show the given value and the percentage e.g 123 (8%)Func< ChartPoint, string> labelPoint = chartPoint => string.Format("{0} ({1:P})", chartPoint.Y, chartPoint.Participation); SeriesCollection piechartData = http://www.srcmini.com/new SeriesCollection{new PieSeries{Title ="First Item", Values = new ChartValues< double> {25}, DataLabels = true, LabelPoint = labelPoint, // Define a custom Color Fill = System.Windows.Media.Brushes.Black}, new PieSeries{Title = "Second Item", Values = new ChartValues< double> {25}, DataLabels = true, LabelPoint = labelPoint, Fill = System.Windows.Media.Brushes.Green, PushOut = 15}, new PieSeries{Title = "Third Item", Values = new ChartValues< double> {25}, DataLabels = true, LabelPoint = labelPoint, Fill = System.Windows.Media.Brushes.Pink}}; // You can add a new item dinamically with the add method of the collectionpiechartData.Add(new PieSeries{Title = "Fourth Item", Values = new ChartValues< double> { 25 }, DataLabels = true, LabelPoint = labelPoint, Fill = System.Windows.Media.Brushes.Gray}); // Define the collection of Values to display in the Pie ChartpieChart1.Series = piechartData; // Set the legend location to appear in the bottom of the chartpieChart1.LegendLocation = LegendLocation.Right;

将生成以下图表：