CustomDrawCrosshairEventArgs.CrosshairElementGroups Property
Provides access to the settings of crosshair elements and crosshair group header elements to customize their appearance.
Namespace: DevExpress.Xpf.Charts
Assembly: DevExpress.Xpf.Charts.v21.2.dll
NuGet Package: DevExpress.Wpf.Charts
Declaration
Property Value
Type | Description |
---|---|
List<CrosshairElementGroup> | An object implementing the System.Collections.IList interface that represents the CrosshairElementGroup collection. |
Remarks
Use the CrosshairElementGroups property to get access to the settings of a crosshair element group when handling the ChartControl.CustomDrawCrosshair event. After that, you can access the appearance settings of crosshair elements using the CrosshairElementGroup.CrosshairElements property and crosshair group header elements using the CrosshairElementGroup.HeaderElement property.
Example
This example shows how to use the ChartControl.CustomDrawCrosshair event to customize the crosshair cursor. For example, you can use this event to paint crosshair label items depending on the highlighted point value. In this example, the ChartControl.CustomDrawCrosshair
event is invoked when you click the Custom Draw Crosshair Cursor button on the form.
Enable the following properties before the crosshair is customized to display crosshair axis lines and labels:
- CrosshairOptions.ShowArgumentLabels
- CrosshairOptions.ShowArgumentLine
- CrosshairOptions.ShowValueLabels
- CrosshairOptions.ShowValueLine
<Window x:Class="CrosshairCustomDraw.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:dxc="http://schemas.devexpress.com/winfx/2008/xaml/charts"
Title="MainWindow" Height="414" Width="525">
<Grid>
<StackPanel>
<dxc:ChartControl Name="chartControl1" Height="340"
CustomDrawCrosshair="chartControl1_CustomDrawCrosshair">
<dxc:ChartControl.CrosshairOptions>
<dxc:CrosshairOptions ShowArgumentLabels="True"
ShowArgumentLine="True"
ShowValueLabels="True"
ShowValueLine="True"/>
</dxc:ChartControl.CrosshairOptions>
<dxc:XYDiagram2D>
<dxc:XYDiagram2D.AxisX>
<dxc:AxisX2D>
<dxc:AxisX2D.CrosshairAxisLabelOptions>
<dxc:CrosshairAxisLabelOptions Pattern="{}{V:f1}"/>
</dxc:AxisX2D.CrosshairAxisLabelOptions>
</dxc:AxisX2D>
</dxc:XYDiagram2D.AxisX>
<dxc:LineSeries2D DisplayName="Series1">
<dxc:SeriesPoint Argument="1" Value="50"/>
<dxc:SeriesPoint Argument="2" Value="44"/>
<dxc:SeriesPoint Argument="3" Value="55"/>
<dxc:SeriesPoint Argument="4" Value="77"/>
</dxc:LineSeries2D>
<dxc:LineSeries2D DisplayName="Series2">
<dxc:SeriesPoint Argument="1" Value="22"/>
<dxc:SeriesPoint Argument="2" Value="11"/>
<dxc:SeriesPoint Argument="3" Value="9"/>
<dxc:SeriesPoint Argument="4" Value="8"/>
</dxc:LineSeries2D>
</dxc:XYDiagram2D>
</dxc:ChartControl>
<Button Height="35" Content="Custom Draw Crosshair Cursor" Click="Button_Click"></Button>
</StackPanel>
</Grid>
</Window>
using System.Windows;
using DevExpress.Xpf.Charts;
using System.Windows.Media;
namespace CrosshairCustomDraw {
public partial class MainWindow : Window {
bool handleCustomDraw;
public MainWindow() {
InitializeComponent();
}
private void Button_Click(object sender, RoutedEventArgs e) {
handleCustomDraw = true;
chartControl1.CustomDrawCrosshair += chartControl1_CustomDrawCrosshair;
}
private void chartControl1_CustomDrawCrosshair(object sender, CustomDrawCrosshairEventArgs e) {
if (!handleCustomDraw) return;
// Specify the crosshair argument line color, dash style and thickness.
e.CrosshairLineElement.Brush = Brushes.Aqua;
e.CrosshairLineElement.LineStyle.DashStyle = DashStyles.DashDot;
e.CrosshairLineElement.LineStyle.Thickness = 3;
// Specify the back color for crosshair argument label.
foreach (CrosshairAxisLabelElement axisLabelElement in e.CrosshairAxisLabelElements)
axisLabelElement.Background = Brushes.Blue;
foreach (CrosshairElementGroup group in e.CrosshairElementGroups) {
CrosshairElement element = group.CrosshairElements[0];
// Specify the color, dash style and thickness for the crosshair value lines.
element.LineElement.Brush = Brushes.DarkViolet;
element.LineElement.LineStyle.DashStyle = DashStyles.Dash;
element.LineElement.LineStyle.Thickness = 2;
// Specify the font size and background for the crosshair value labels.
element.AxisLabelElement.FontSize = 14;
element.AxisLabelElement.Background = Brushes.Red;
// Specify the foreground and font size for the crosshair cursor label that shows series.
if (element.SeriesPoint.Value > 50) {
element.LabelElement.Foreground = Brushes.Green;
element.LabelElement.FontSize = 14;
}
}
foreach (CrosshairElementGroup group in e.CrosshairElementGroups) {
CrosshairGroupHeaderElement groupHeaderElement = group.HeaderElement;
// Specify the text, text color and font for the crosshair group header element.
groupHeaderElement.Text = "Custom draw";
groupHeaderElement.Foreground = Brushes.Red;
groupHeaderElement.FontSize = 15;
}
}
}
}