Application.Deactivated Event

A Windows Presentation Foundation (WPF) application that has one or more open windows deactivates (stops being the foreground application) when a user does the following:

• Switches to another application by using ALT+TAB or by using Task Manager.

• Clicks the taskbar button for a window in another application.

Applications that need to detect deactivation can handle the Deactivated 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 Deactivated and Activated events to determine which state it's in.

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

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

<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; // EventArgs 
using System.Windows; // Application 

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;
        }
    }
}

.NET Framework

.NET Framework Client Profile

Reference