圆环图

圆环图 是由 DoughnutSeriesView 对象来表示的，此对象属于饼、圆环和漏斗系列。当需要比较相同系列中不同点参数的百分比取值时、并且以易于理解的圆环切块来说明这些取值时，使用这种视图。

在下面的插图中显示了一个圆环图。注意，如果图表包含多个 DoughnutSeriesView (以及 PieSeriesView) 类型的系列，那么就根据 SimpleDiagram.Dimension 和 SimpleDiagram.LayoutDirection 属性值，在相同的图象中显示所有这些系列。

注意，要控制圆环内孔的尺寸，则使用 DoughnutSeriesView.HoleRadiusPercent (或 Doughnut3DSeriesView.HoleRadiusPercent) 属性。例如，在上面的插图中，左侧图表的此属性值被设置为 0。

下表列出了这种图表类型的主要特征。

特征	取值
系列视图类型	DoughnutSeriesView
图象类型	2D- SimpleDiagram
每个数据点的参数个数	1
每个数据点的取值个数	1

注意
要获得关于哪些图表类型可以与圆环图组合使用的信息，请参阅组合使用不同的系列视图文档。

下面的示例演示了在运行时刻如何创建 ChartControl (拥有一个 DoughnutSeriesView 类型的系列)，设置它的常规属性，并把图表添加到窗体中。在继续本示例之前，首先要在 Visual Studio 中创建一个 Windows 窗体应用程序，并把所有必需的程序集包含到项目的“引用”列表中。

然后，把下列代码添加到 Form.Load 事件处理程序。

C#	复制代码
using System; using System.Windows.Forms; using DevExpress.XtraCharts; // ... private void Form1_Load(object sender, EventArgs e) { // Create a new chart. ChartControl DoughnutChart = new ChartControl(); // Create a doughnut series. Series series1 = new Series("Series 1", ViewType.Doughnut); // Populate the series with points. series1.Points.Add(new SeriesPoint("Russia", 17.0752)); series1.Points.Add(new SeriesPoint("Canada", 9.98467)); series1.Points.Add(new SeriesPoint("USA", 9.63142)); series1.Points.Add(new SeriesPoint("China", 9.59696)); series1.Points.Add(new SeriesPoint("Brazil", 8.511965)); series1.Points.Add(new SeriesPoint("Australia", 7.68685)); series1.Points.Add(new SeriesPoint("India", 3.28759)); series1.Points.Add(new SeriesPoint("Others", 81.2)); // Add the series to the chart. DoughnutChart.Series.Add(series1); // Adjust the value numeric options of the series. series1.PointOptions.ValueNumericOptions.Format = NumericFormat.Percent; series1.PointOptions.ValueNumericOptions.Precision = 0; // Specify how series points are sorted. series1.SeriesPointsSorting = SortingMode.Ascending; series1.SeriesPointsSortingKey = SeriesPointKey.Argument; // Specify the behavior of series labels. ((DoughnutSeriesLabel)series1.Label).Position = PieSeriesLabelPosition.TwoColumns; ((DoughnutSeriesLabel)series1.Label).ResolveOverlappingMode = ResolveOverlappingMode.Default; ((DoughnutSeriesLabel)series1.Label).ResolveOverlappingMinIndent = 5; ((PiePointOptions)series1.PointOptions).PointView = PointView.ArgumentAndValues; // Adjust the view-type-specific options of the series. ((DoughnutSeriesView)series1.View).ExplodedPoints.Add(series1.Points[0]); ((DoughnutSeriesView)series1.View).ExplodedDistancePercentage = 30; // Access the diagram's options. ((SimpleDiagram)DoughnutChart.Diagram).Dimension = 2; // Add a title to the chart and hide the legend. ChartTitle chartTitle1 = new ChartTitle(); chartTitle1.Text = "3D Doughnut Chart"; DoughnutChart.Titles.Add(chartTitle1); DoughnutChart.Legend.Visible = false; // Add the chart to the form. DoughnutChart.Dock = DockStyle.Fill; this.Controls.Add(DoughnutChart); }

C#

复制代码

using System;
using System.Windows.Forms;
using DevExpress.XtraCharts;
// ...

private void Form1_Load(object sender, EventArgs e) {
    // Create a new chart.
    ChartControl DoughnutChart = new ChartControl();

    // Create a doughnut series.
    Series series1 = new Series("Series 1", ViewType.Doughnut);

    // Populate the series with points.
    series1.Points.Add(new SeriesPoint("Russia", 17.0752));
    series1.Points.Add(new SeriesPoint("Canada", 9.98467));
    series1.Points.Add(new SeriesPoint("USA", 9.63142));
    series1.Points.Add(new SeriesPoint("China", 9.59696));
    series1.Points.Add(new SeriesPoint("Brazil", 8.511965));
    series1.Points.Add(new SeriesPoint("Australia", 7.68685));
    series1.Points.Add(new SeriesPoint("India", 3.28759));
    series1.Points.Add(new SeriesPoint("Others", 81.2));

    // Add the series to the chart.
    DoughnutChart.Series.Add(series1);

    // Adjust the value numeric options of the series.
    series1.PointOptions.ValueNumericOptions.Format = NumericFormat.Percent;
    series1.PointOptions.ValueNumericOptions.Precision = 0;

    // Specify how series points are sorted.
    series1.SeriesPointsSorting = SortingMode.Ascending;
    series1.SeriesPointsSortingKey = SeriesPointKey.Argument;

    // Specify the behavior of series labels.
    ((DoughnutSeriesLabel)series1.Label).Position = PieSeriesLabelPosition.TwoColumns;
    ((DoughnutSeriesLabel)series1.Label).ResolveOverlappingMode = ResolveOverlappingMode.Default;
    ((DoughnutSeriesLabel)series1.Label).ResolveOverlappingMinIndent = 5;
    ((PiePointOptions)series1.PointOptions).PointView = PointView.ArgumentAndValues;
    
    // Adjust the view-type-specific options of the series.
    ((DoughnutSeriesView)series1.View).ExplodedPoints.Add(series1.Points[0]);
    ((DoughnutSeriesView)series1.View).ExplodedDistancePercentage = 30;

    // Access the diagram's options.
    ((SimpleDiagram)DoughnutChart.Diagram).Dimension = 2;

    // Add a title to the chart and hide the legend.
    ChartTitle chartTitle1 = new ChartTitle();
    chartTitle1.Text = "3D Doughnut Chart";
    DoughnutChart.Titles.Add(chartTitle1);
    DoughnutChart.Legend.Visible = false;

    // Add the chart to the form.
    DoughnutChart.Dock = DockStyle.Fill;
    this.Controls.Add(DoughnutChart);
}

Visual Basic	复制代码
Imports System Imports System.Windows.Forms Imports DevExpress.XtraCharts ' ... Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) Handles MyBase.Load ' Create a new chart. Dim DoughnutChart As New ChartControl() ' Create a doughnut series. Dim series1 As New Series("Series 1", ViewType.Doughnut) ' Populate the series with points. series1.Points.Add(New SeriesPoint("Russia", 17.0752)) series1.Points.Add(New SeriesPoint("Canada", 9.98467)) series1.Points.Add(New SeriesPoint("USA", 9.63142)) series1.Points.Add(New SeriesPoint("China", 9.59696)) series1.Points.Add(New SeriesPoint("Brazil", 8.511965)) series1.Points.Add(New SeriesPoint("Australia", 7.68685)) series1.Points.Add(New SeriesPoint("India", 3.28759)) series1.Points.Add(New SeriesPoint("Others", 81.2)) ' Add the series to the chart. DoughnutChart.Series.Add(series1) ' Adjust the value numeric options of the series. series1.PointOptions.ValueNumericOptions.Format = NumericFormat.Percent series1.PointOptions.ValueNumericOptions.Precision = 0 ' Specify how series points are sorted. series1.SeriesPointsSorting = SortingMode.Ascending series1.SeriesPointsSortingKey = SeriesPointKey.Argument ' Specify the behavior of series labels. CType(series1.Label, DoughnutSeriesLabel).Position = PieSeriesLabelPosition.TwoColumns CType(series1.Label, DoughnutSeriesLabel).ResolveOverlappingMode = _ ResolveOverlappingMode.Default CType(series1.Label, DoughnutSeriesLabel).ResolveOverlappingMinIndent = 5 CType(series1.PointOptions, PiePointOptions).PointView = PointView.ArgumentAndValues ' Adjust the view-type-specific options of the series. CType(series1.View, DoughnutSeriesView).ExplodedPoints.Add(series1.Points(0)) CType(series1.View, DoughnutSeriesView).ExplodedDistancePercentage = 30 ' Access the diagram's options. CType(DoughnutChart.Diagram, SimpleDiagram).Dimension = 2 ' Add a title to the chart and hide the legend. Dim chartTitle1 As New ChartTitle() chartTitle1.Text = "3D Doughnut Chart" DoughnutChart.Titles.Add(chartTitle1) DoughnutChart.Legend.Visible = False ' Add the chart to the form. DoughnutChart.Dock = DockStyle.Fill Me.Controls.Add(DoughnutChart) End Sub

Visual Basic

复制代码

Imports System
Imports System.Windows.Forms
Imports DevExpress.XtraCharts
' ...

Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) Handles MyBase.Load
    ' Create a new chart.
    Dim DoughnutChart As New ChartControl()

    ' Create a doughnut series.
    Dim series1 As New Series("Series 1", ViewType.Doughnut)

    ' Populate the series with points.
    series1.Points.Add(New SeriesPoint("Russia", 17.0752))
    series1.Points.Add(New SeriesPoint("Canada", 9.98467))
    series1.Points.Add(New SeriesPoint("USA", 9.63142))
    series1.Points.Add(New SeriesPoint("China", 9.59696))
    series1.Points.Add(New SeriesPoint("Brazil", 8.511965))
    series1.Points.Add(New SeriesPoint("Australia", 7.68685))
    series1.Points.Add(New SeriesPoint("India", 3.28759))
    series1.Points.Add(New SeriesPoint("Others", 81.2))

    ' Add the series to the chart.
    DoughnutChart.Series.Add(series1)

    ' Adjust the value numeric options of the series.
    series1.PointOptions.ValueNumericOptions.Format = NumericFormat.Percent
    series1.PointOptions.ValueNumericOptions.Precision = 0

    ' Specify how series points are sorted.
    series1.SeriesPointsSorting = SortingMode.Ascending
    series1.SeriesPointsSortingKey = SeriesPointKey.Argument

    ' Specify the behavior of series labels.
    CType(series1.Label, DoughnutSeriesLabel).Position = PieSeriesLabelPosition.TwoColumns
    CType(series1.Label, DoughnutSeriesLabel).ResolveOverlappingMode = _ 
        ResolveOverlappingMode.Default
    CType(series1.Label, DoughnutSeriesLabel).ResolveOverlappingMinIndent = 5
    CType(series1.PointOptions, PiePointOptions).PointView = PointView.ArgumentAndValues

    ' Adjust the view-type-specific options of the series.
    CType(series1.View, DoughnutSeriesView).ExplodedPoints.Add(series1.Points(0))
    CType(series1.View, DoughnutSeriesView).ExplodedDistancePercentage = 30

    ' Access the diagram's options.
    CType(DoughnutChart.Diagram, SimpleDiagram).Dimension = 2

    ' Add a title to the chart and hide the legend.
    Dim chartTitle1 As New ChartTitle()
    chartTitle1.Text = "3D Doughnut Chart"
    DoughnutChart.Titles.Add(chartTitle1)
    DoughnutChart.Legend.Visible = False

    ' Add the chart to the form.
    DoughnutChart.Dock = DockStyle.Fill
    Me.Controls.Add(DoughnutChart)
End Sub

Show Me
在 DevExpress Code Central 数据库中可以找到完整的示例项目，网址是 http://www.devexpress.com/example=E1047。取决于目标平台类型 (ASP.NET、WinForms 等)，可以在线运行本示例，或者下载自动可执行的示例。

简单的图像

简要说明

图表类型特征

示例

参阅