ChartHitInfo Class

Contains information about a specific point within a chart.

Namespace: DevExpress.Xpf.Charts

Assembly: DevExpress.Xpf.Charts.v19.2.dll

Declaration

C#

public class ChartHitInfo :
    ChartHitInfoBase

VB.NET

Public Class ChartHitInfo
    Inherits ChartHitInfoBase

Related API Members

The following members return ChartHitInfo objects:

• ChartControl.CalcHitInfo(Point, Double)
• ChartControl.CalcHitInfo(Point)

Remarks

ChartHitInfo objects can be created by calling the chart’s ChartControl.CalcHitInfo method. This method requires the test point as a parameter, or its coordinates.

The ChartHitInfo class properties can be grouped into two categories:

• The properties that indicate whether the test point resides over a particular view element. For instance, the ChartHitInfoBase.InAxis property indicates whether the test point is over the axis;
• The properties identifying the topmost visual element, which contains the test point (e.g. ChartHitInfoBase.Axis).

Example

This example demonstrates how to calculate the hit information for the chart element over which the mouse pointer is hovering.

To accomplish this, handle the ChartControl.MouseMove event, obtain the current chart element via the ChartControl.CalcHitInfo method, and if the element is not null (Nothing in Visual Basic), display its information.

Note

A complete sample project is available at https://github.com/DevExpress-Examples/how-to-determine-which-chart-element-is-hovered-by-the-mouse-pointer-e4511.

MainWindow.xaml.cs

using System.Windows;
using System.Windows.Input;
using DevExpress.Xpf.Charts;
using System.Text;

namespace DetermineHoveredChartElement
{

    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void chartControl1_MouseMove(object sender, MouseEventArgs e)
        {
            // Obtain hit information under the test point.
            ChartHitInfo hitInfo = chartControl1.CalcHitInfo(e.GetPosition(chartControl1));
            StringBuilder builder = new StringBuilder();

            // Check  whether the chart element is under the test point and if so - obtain the element's content.
            if (hitInfo.InDiagram)
                builder.AppendLine("In diagram");
            if (hitInfo.InAxis)
                builder.AppendLine("In axis:" + hitInfo.Axis.Name);
            if (hitInfo.AxisLabel != null)
                builder.AppendLine("Axis Label:\n" + hitInfo.AxisLabel.Name);
            if (hitInfo.AxisTitle != null)
                builder.AppendLine("Axis title:\n" + hitInfo.AxisTitle.Content);
            if (hitInfo.InTitle)
                builder.AppendLine("In chart title:\n " + hitInfo.Title.Content);
            if (hitInfo.InLegend)
                builder.AppendLine("In legend");
            if (hitInfo.InSeries)
                builder.AppendLine("In series: " + hitInfo.Series.Name);
            if (hitInfo.InSeriesLabel)
            {
                builder.AppendLine("In series label");
                builder.AppendLine("Series Label:" + hitInfo.SeriesLabel.Name);
            }

            if (hitInfo.InSeriesPoint)
            {
                builder.AppendLine("Argument: " + hitInfo.SeriesPoint.Argument);
                builder.AppendLine("Value: " + hitInfo.SeriesPoint.Value);
            }

            // Show hit-testing results 
            if (builder.Length > 0)
                text1.Content = string.Format("Hit-testing results:\n" + builder.ToString());
            else
                text1.Content = "Move the mouse\n pointer over\n the chart to see\n information on\n hovered chart\n elements.";
        }
    }
}

MainWindow.xaml

<Window x:Class="DetermineHoveredChartElement.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525" 
        xmlns:dxc="http://schemas.devexpress.com/winfx/2008/xaml/charts">

    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="130"/>
            <ColumnDefinition />
        </Grid.ColumnDefinitions>
        <StackPanel  Grid.Row="0" Grid.Column="0" >
            <Label Name="text1"/>
        </StackPanel>
        <dxc:ChartControl Grid.Row="0" Grid.Column="1" Name="chartControl1"
                          CrosshairEnabled="False" 
                          MouseMove="chartControl1_MouseMove">
            <dxc:XYDiagram2D >
                <dxc:BarSideBySideSeries2D  x:Name="series1" LabelsVisibility="True" 
                                            DisplayName="Series1">
                    <dxc:SeriesPoint Argument="A" Value="1" />
                    <dxc:SeriesPoint Argument="B" Value="2" />
                    <dxc:SeriesPoint Argument="C" Value="3" />
                    <dxc:SeriesPoint Argument="D" Value="4" />
                </dxc:BarSideBySideSeries2D>
                <dxc:BarSideBySideSeries2D x:Name="series2" LabelsVisibility="True" 
                                           DisplayName="Series2">
                    <dxc:SeriesPoint Argument="A" Value="4" />
                    <dxc:SeriesPoint Argument="B" Value="3" />
                    <dxc:SeriesPoint Argument="C" Value="2" />
                    <dxc:SeriesPoint Argument="D" Value="1" />
                </dxc:BarSideBySideSeries2D>
                <dxc:XYDiagram2D.AxisY>
                    <dxc:AxisY2D >
                        <dxc:AxisY2D.Title>
                            <dxc:AxisTitle Content="AxisY Title"/>
                        </dxc:AxisY2D.Title>
                        <dxc:AxisY2D.Label>
                            <dxc:AxisLabel Name="AxisYLabel" />
                        </dxc:AxisY2D.Label>
                    </dxc:AxisY2D>
                </dxc:XYDiagram2D.AxisY>
                <dxc:XYDiagram2D.AxisX>
                    <dxc:AxisX2D>
                        <dxc:AxisX2D.Label>
                            <dxc:AxisLabel  Name="AxisXLabel"/>
                        </dxc:AxisX2D.Label>
                    </dxc:AxisX2D>
                </dxc:XYDiagram2D.AxisX>
            </dxc:XYDiagram2D>
            <dxc:ChartControl.Titles>
                <dxc:Title Content="My Chart" />
            </dxc:ChartControl.Titles>
            <dxc:ChartControl.Legend>
                <dxc:Legend />
            </dxc:ChartControl.Legend>
        </dxc:ChartControl>
    </Grid>
</Window>

MainWindow.xaml.vb

Imports Microsoft.VisualBasic
Imports System.Windows
Imports System.Windows.Input
Imports DevExpress.Xpf.Charts
Imports System.Text

Namespace DetermineHoveredChartElement

    Partial Public Class MainWindow
        Inherits Window
        Public Sub New()
            InitializeComponent()
        End Sub

        Private Sub chartControl1_MouseMove(ByVal sender As Object, ByVal e As MouseEventArgs)
            ' Obtain hit information under the test point.
            Dim hitInfo As ChartHitInfo = chartControl1.CalcHitInfo(e.GetPosition(chartControl1))
            Dim builder As New StringBuilder()

            ' Check  whether the chart element is under the test point and if so - obtain the element's content.
            If hitInfo.InDiagram Then
                builder.AppendLine("In diagram")
            End If
            If hitInfo.InAxis Then
                builder.AppendLine("In axis:" & hitInfo.Axis.Name)
            End If
            If hitInfo.AxisLabel IsNot Nothing Then
                builder.AppendLine("Axis Label:" & Constants.vbLf + hitInfo.AxisLabel.Name)
            End If
            If hitInfo.AxisTitle IsNot Nothing Then
                builder.AppendLine("Axis title:" & Constants.vbLf + hitInfo.AxisTitle.Content)
            End If
            If hitInfo.InTitle Then
                builder.AppendLine("In chart title:" & Constants.vbLf & " " & hitInfo.Title.Content)
            End If
            If hitInfo.InLegend Then
                builder.AppendLine("In legend")
            End If
            If hitInfo.InSeries Then
                builder.AppendLine("In series: " & hitInfo.Series.Name)
            End If
            If hitInfo.InSeriesLabel Then
                builder.AppendLine("In series label")
                builder.AppendLine("Series Label:" & hitInfo.SeriesLabel.Name)
            End If

            If hitInfo.InSeriesPoint Then
                builder.AppendLine("Argument: " & hitInfo.SeriesPoint.Argument)
                builder.AppendLine("Value: " & hitInfo.SeriesPoint.Value)
            End If

            ' Show hit-testing results 
            If builder.Length > 0 Then
                text1.Content = String.Format("Hit-testing results:" & Constants.vbLf + builder.ToString())
            Else
                text1.Content = "Move the mouse" & Constants.vbLf & " pointer over" & Constants.vbLf & " the chart to see" & Constants.vbLf & " information on" & Constants.vbLf & " hovered chart" & Constants.vbLf & " elements."
            End If
        End Sub
    End Class
End Namespace

Related GitHub Examples

The following code snippet (auto-collected from DevExpress Examples) contains a reference to the ChartHitInfo class.

Note

The algorithm used to collect these code examples remains a work in progress. Accordingly, the links and snippets below may produce inaccurate results. If you encounter an issue with code examples below, please use the feedback form on this page to report the issue.

VB.NET

how-to-determine-which-chart-element-is-hovered-by-the-mouse-pointer-e4511/VB/DetermineHoveredChartElement/MainWindow.xaml.vb#L17

' Obtain hit information under the test point.
Dim hitInfo As ChartHitInfo = chartControl1.CalcHitInfo(e.GetPosition(chartControl1))
Dim builder As New StringBuilder()

Inheritance

Object

ChartHitInfoBase

ChartHitInfo