IndicatorLeaveEventHandler Delegate

A method that will handle the RangeBase.IndicatorLeave event.

Namespace: DevExpress.Xpf.Gauges

Assembly: DevExpress.Xpf.Gauges.v21.2.dll

NuGet Package: DevExpress.Wpf.Gauges

Declaration

C#

public delegate void IndicatorLeaveEventHandler(
    object sender,
    IndicatorLeaveEventArgs e
);

VB.NET

Public Delegate Sub IndicatorLeaveEventHandler(
    sender As Object,
    e As IndicatorLeaveEventArgs
)

Parameters

Name	Type	Description
sender	Object	The event source.
e	IndicatorLeaveEventArgs	An IndicatorLeaveEventArgs object that contains event data.

Example

In some cases, you need to know whether the current value of an indicator is within a particular range. This example shows how to create a state indicator that changes its color depending on the current range.

First, the Circular gauge is created with three ranges and two empty sections. By default, the gauge’s needle doesn’t belong to any range, so the state indicator is painted as a gray ellipse.

To solve this task it’s necessary to handle the RangeBase.IndicatorEnter and RangeBase.IndicatorLeave events in the following way:

• if a needle ‘enters’ a range, it is painted with the range color;

• if a needle ‘leaves’ a range, it is painted in gray.

Note

In this example we set the ValueIndicatorBase.IsInteractive property to True, so that you can click on a gauge and manually change the current needle value.

View Example

MainWindow.xaml.vb

Imports Microsoft.VisualBasic
Imports System.Windows
Imports System.Windows.Media
Imports DevExpress.Xpf.Gauges

Namespace DXGauges_RangeEvents

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

        Private Sub GreenRange_IndicatorEnter(ByVal sender As Object, ByVal e As IndicatorEnterEventArgs)
            stateIndicator.Fill = New SolidColorBrush(Colors.Green)
        End Sub

        Private Sub GreenRange_IndicatorLeave(ByVal sender As Object, ByVal e As IndicatorLeaveEventArgs)
            stateIndicator.Fill = New SolidColorBrush(Colors.Gray)
        End Sub

        Private Sub YellowRange_IndicatorEnter(ByVal sender As Object, ByVal e As IndicatorEnterEventArgs)
            stateIndicator.Fill = New SolidColorBrush(Colors.Yellow)
        End Sub

        Private Sub YellowRange_IndicatorLeave(ByVal sender As Object, ByVal e As IndicatorLeaveEventArgs)
            If ((e.NewValue) < 10) OrElse (((e.NewValue) > 90)) Then
                stateIndicator.Fill = New SolidColorBrush(Colors.Gray)
            End If
        End Sub

        Private Sub RedRange_IndicatorEnter(ByVal sender As Object, ByVal e As IndicatorEnterEventArgs)
            stateIndicator.Fill = New SolidColorBrush(Colors.Red)
        End Sub

        Private Sub RedRange_IndicatorLeave(ByVal sender As Object, ByVal e As IndicatorLeaveEventArgs)
            If ((e.NewValue) < 10) OrElse (((e.NewValue) > 90)) Then
                stateIndicator.Fill = New SolidColorBrush(Colors.Gray)
            End If
        End Sub
    End Class
End Namespace

MainWindow.xaml

<Window x:Class="DXGauges_RangeEvents.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:dxga="http://schemas.devexpress.com/winfx/2008/xaml/gauges"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition/>
            <RowDefinition/>
        </Grid.RowDefinitions>
        <!--State indicator represented by Ellipse-->
        <Ellipse x:Name="stateIndicator" Grid.Row="1"
                 Width="50" Height="50" 
                 Fill="Gray" />
        <!---->
        <dxga:CircularGaugeControl Grid.RowSpan="2"
                                   EnableAnimation= "True">
            <dxga:CircularGaugeControl.Scales>
                <dxga:ArcScale>
                    <dxga:ArcScale.Needles>
                        <dxga:ArcScaleNeedle IsInteractive="True" />
                    </dxga:ArcScale.Needles>
                    <dxga:ArcScale.Ranges>
                        <dxga:ArcScaleRange StartValue="10" EndValue="30"  
                                            IndicatorEnter="GreenRange_IndicatorEnter" 
                                            IndicatorLeave="GreenRange_IndicatorLeave"/>
                        <dxga:ArcScaleRange StartValue="30" EndValue="60"  
                                            IndicatorEnter="YellowRange_IndicatorEnter" 
                                            IndicatorLeave="YellowRange_IndicatorLeave" />
                        <dxga:ArcScaleRange StartValue="60" EndValue="90" 
                                            IndicatorEnter="RedRange_IndicatorEnter"   
                                            IndicatorLeave="RedRange_IndicatorLeave"/>
                    </dxga:ArcScale.Ranges>
                </dxga:ArcScale>
            </dxga:CircularGaugeControl.Scales>
        </dxga:CircularGaugeControl>
    </Grid>
</Window>

MainWindow.xaml.cs

using System.Windows;
using System.Windows.Media;
using DevExpress.Xpf.Gauges;

namespace DXGauges_RangeEvents {

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

        private void GreenRange_IndicatorEnter(object sender, IndicatorEnterEventArgs e) {
            stateIndicator.Fill = new SolidColorBrush(Colors.Green);
        }

        private void GreenRange_IndicatorLeave(object sender, IndicatorLeaveEventArgs e) {
            stateIndicator.Fill = new SolidColorBrush(Colors.Gray);
        }

        private void YellowRange_IndicatorEnter(object sender, IndicatorEnterEventArgs e) {
            stateIndicator.Fill = new SolidColorBrush(Colors.Yellow);
        }

        private void YellowRange_IndicatorLeave(object sender, IndicatorLeaveEventArgs e) {
            if (((e.NewValue) < 10) || (((e.NewValue) > 90)))
                stateIndicator.Fill = new SolidColorBrush(Colors.Gray);
        }

        private void RedRange_IndicatorEnter(object sender, IndicatorEnterEventArgs e) {
            stateIndicator.Fill = new SolidColorBrush(Colors.Red);
        }

        private void RedRange_IndicatorLeave(object sender, IndicatorLeaveEventArgs e) {
            if (((e.NewValue) < 10) || (((e.NewValue) > 90)))
                stateIndicator.Fill = new SolidColorBrush(Colors.Gray);
        }
    }
}