Application.Activated Event

Reference

Definition

Namespace:: System.Windows

Assembly:: PresentationFramework.dll

Important

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Occurs when an application becomes the foreground application.

public:
 event EventHandler ^ Activated;

public event EventHandler Activated;

member this.Activated : EventHandler

Public Custom Event Activated As EventHandler

Public Event Activated As EventHandler

Event Type

EventHandler

Examples

The following example shows how to detect when a standalone application activates and deactivates.

XAML

<Application 
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  x:Class="SDKSample.App"
  StartupUri="MainWindow.xaml"
  Activated="App_Activated" 
  Deactivated="App_Deactivated" />

using System;
using System.Windows;

namespace SDKSample
{
    public partial class App : Application
    {
        bool isApplicationActive;

        void App_Activated(object sender, EventArgs e)
        {
            // Application activated
            this.isApplicationActive = true;
        }

        void App_Deactivated(object sender, EventArgs e)
        {
            // Application deactivated
            this.isApplicationActive = false;
        }
    }
}


Imports System.Windows

Namespace SDKSample
    Partial Public Class App
        Inherits Application
        Private isApplicationActive As Boolean

        Private Sub App_Activated(ByVal sender As Object, ByVal e As EventArgs)
            ' Application activated
            Me.isApplicationActive = True
        End Sub

        Private Sub App_Deactivated(ByVal sender As Object, ByVal e As EventArgs)
            ' Application deactivated
            Me.isApplicationActive = False
        End Sub
    End Class
End Namespace

Remarks

A Windows Presentation Foundation application that has one or more open windows is activated (becomes the foreground application) when one of the windows is activated for the first time since the application was launched, or when one of the windows is activated while the application is inactive: Specifically, activation occurs when:

An application opens its first window.
A user switches to the application by using ALT+TAB or by using Task Manager.
A user clicks the taskbar button for one of the windows in an application.

Applications that need to detect when they activate can handle the Activated event.

After an application is first activated, it may be deactivated and reactivated many times during its lifetime. If an application's behavior or state depends on its activation state, it can handle both Activated and Deactivated events to determine which activation state it's in.

Once an application becomes active, Activated will not be raised again until the application is deactivated, irrespective of how many windows within an application are activated while the application is active.

Activated is not raised for XAML browser applications (XBAPs).

Applies to

Product	Versions
.NET Framework	3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
Windows Desktop	3.0, 3.1, 5, 6, 7, 8, 9, 10

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