饼图

饼图是由 PieSeriesView 对象来表示的，此对象属于饼、圆环和漏斗系列视图。当需要比较相同系列中不同点参数的百分比取值、并且以易于理解的饼切块说明这些取值时，这种视图是有用的。

在下面的插图中显示了一个饼图。注意，如果图表包含多个 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。

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	PieSeriesView
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饼图组合使用的信息，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 PieSeriesView 类型的系列)，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 DevExpress.XtraCharts; // ... private void Form1_Load(object sender, EventArgs e) { // Create an empty chart. ChartControl pieChart = new ChartControl(); // Create a pie series. Series series1 = new Series("A Pie Series", ViewType.Pie); // 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. pieChart.Series.Add(series1); // Adjust the point options of the series. series1.PointOptions.PointView = PointView.ArgumentAndValues; series1.PointOptions.ValueNumericOptions.Format = NumericFormat.Percent; series1.PointOptions.ValueNumericOptions.Precision = 0; // Detect overlapping of series labels. ((PieSeriesLabel)series1.Label).ResolveOverlappingMode = ResolveOverlappingMode.Default; // Access the view-type-specific options of the series. PieSeriesView myView = (PieSeriesView)series1.View; // Show a title for the series. myView.Titles.Add(new SeriesTitle()); myView.Titles[0].Text = series1.Name; // Specify a data filter to explode points. myView.ExplodedPointsFilters.Add(new SeriesPointFilter(SeriesPointKey.Value_1, DataFilterCondition.GreaterThanOrEqual, 9)); myView.ExplodedPointsFilters.Add(new SeriesPointFilter(SeriesPointKey.Argument, DataFilterCondition.NotEqual, "Others")); myView.ExplodeMode = PieExplodeMode.UseFilters; myView.ExplodedDistancePercentage = 30; myView.RuntimeExploding = true; myView.HeightToWidthRatio = 99; // Hide the legend (if necessary). pieChart.Legend.Visible = false; // Add the chart to the form. pieChart.Dock = DockStyle.Fill; this.Controls.Add(pieChart); }

C#

复制代码

using DevExpress.XtraCharts;
// ...

private void Form1_Load(object sender, EventArgs e) {
    // Create an empty chart.
    ChartControl pieChart = new ChartControl();

    // Create a pie series.
    Series series1 = new Series("A Pie Series", ViewType.Pie);

    // 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.
    pieChart.Series.Add(series1);

    // Adjust the point options of the series.
    series1.PointOptions.PointView = PointView.ArgumentAndValues;
    series1.PointOptions.ValueNumericOptions.Format = NumericFormat.Percent;
    series1.PointOptions.ValueNumericOptions.Precision = 0;

    // Detect overlapping of series labels.
    ((PieSeriesLabel)series1.Label).ResolveOverlappingMode = 
        ResolveOverlappingMode.Default;

    // Access the view-type-specific options of the series.
    PieSeriesView myView = (PieSeriesView)series1.View;

    // Show a title for the series.
    myView.Titles.Add(new SeriesTitle());
    myView.Titles[0].Text = series1.Name;

    // Specify a data filter to explode points.
    myView.ExplodedPointsFilters.Add(new SeriesPointFilter(SeriesPointKey.Value_1,
        DataFilterCondition.GreaterThanOrEqual, 9));
    myView.ExplodedPointsFilters.Add(new SeriesPointFilter(SeriesPointKey.Argument,
        DataFilterCondition.NotEqual, "Others"));
    myView.ExplodeMode = PieExplodeMode.UseFilters;
    myView.ExplodedDistancePercentage = 30;
    myView.RuntimeExploding = true;
    myView.HeightToWidthRatio = 99;

    // Hide the legend (if necessary).
    pieChart.Legend.Visible = false;

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

Visual Basic	复制代码
Imports DevExpress.XtraCharts ' ... Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) _ Handles MyBase.Load ' Create an empty chart. Dim pieChart As New ChartControl() ' Create a pie series. Dim series1 As New Series("A Pie Series", ViewType.Pie) ' 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. pieChart.Series.Add(series1) ' Adjust the point options of the series. series1.PointOptions.PointView = PointView.ArgumentAndValues series1.PointOptions.ValueNumericOptions.Format = NumericFormat.Percent series1.PointOptions.ValueNumericOptions.Precision = 0 ' Detect overlapping of series labels. CType(series1.Label, PieSeriesLabel).ResolveOverlappingMode = _ ResolveOverlappingMode.Default ' Access the view-type-specific options of the series. Dim myView As PieSeriesView = CType(series1.View, PieSeriesView) ' Show a title for the series. myView.Titles.Add(New SeriesTitle()) myView.Titles(0).Text = series1.Name ' Specify a data filter to explode points. myView.ExplodedPointsFilters.Add(New SeriesPointFilter _ (SeriesPointKey.Value_1, DataFilterCondition.GreaterThanOrEqual, 9)) myView.ExplodedPointsFilters.Add(New SeriesPointFilter _ (SeriesPointKey.Argument, DataFilterCondition.NotEqual, "Others")) myView.ExplodeMode = PieExplodeMode.UseFilters myView.ExplodedDistancePercentage = 30 myView.RuntimeExploding = True myView.HeightToWidthRatio = 99 ' Hide the legend (if necessary). pieChart.Legend.Visible = False ' Add the chart to the form. pieChart.Dock = DockStyle.Fill Me.Controls.Add(pieChart) End Sub

Visual Basic

复制代码

Imports DevExpress.XtraCharts
' ...

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) _
Handles MyBase.Load
    ' Create an empty chart.
    Dim pieChart As New ChartControl()

    ' Create a pie series.
    Dim series1 As New Series("A Pie Series", ViewType.Pie)

    ' 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.
    pieChart.Series.Add(series1)

    ' Adjust the point options of the series.
    series1.PointOptions.PointView = PointView.ArgumentAndValues
    series1.PointOptions.ValueNumericOptions.Format = NumericFormat.Percent
    series1.PointOptions.ValueNumericOptions.Precision = 0

    ' Detect overlapping of series labels.
    CType(series1.Label, PieSeriesLabel).ResolveOverlappingMode = _ 
        ResolveOverlappingMode.Default

    ' Access the view-type-specific options of the series.
    Dim myView As PieSeriesView = CType(series1.View, PieSeriesView)

    ' Show a title for the series.
    myView.Titles.Add(New SeriesTitle())
    myView.Titles(0).Text = series1.Name

    ' Specify a data filter to explode points.
    myView.ExplodedPointsFilters.Add(New SeriesPointFilter _ 
        (SeriesPointKey.Value_1, DataFilterCondition.GreaterThanOrEqual, 9))
    myView.ExplodedPointsFilters.Add(New SeriesPointFilter _ 
        (SeriesPointKey.Argument, DataFilterCondition.NotEqual, "Others"))
    myView.ExplodeMode = PieExplodeMode.UseFilters
    myView.ExplodedDistancePercentage = 30
    myView.RuntimeExploding = True
    myView.HeightToWidthRatio = 99

    ' Hide the legend (if necessary).
    pieChart.Legend.Visible = False

    ' Add the chart to the form.
    pieChart.Dock = DockStyle.Fill
    Me.Controls.Add(pieChart)
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=E1189。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