检查窗口是否处于活动状态WPF

Question

I want to subscribe to the Activated and Deactivated events of the class Application but I can't seem to get it right.

I must be doing something wrong cause It's not working I searched around some and found this http://www.csharphelp.com/2006/08/get-current-window-handle-and-caption-with-windows-api-in-c/ and it just seems way too complicated for such an easy task.

I've been looking around in msdn and I eventually tried this http://msdn.microsoft.com/en-us/library/ms366768.aspx but still not working...

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace derp
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();

            this.Width = 250;
            this.Height = 250;
            this.Title = "derp";

            Application app = new Application();
            app.Activated += Active;

            app.Activated += new EventHandler(Active);


        }

        void Active(object sender, EventArgs args)
        {
            //Do stuff
        }

        void Passive(object sender, EventArgs args)
        {
            //Do stuff
        }
    }
}

Answer 1

I think the issue here is that you are creating a new Application() and not referencing the actual current one running.

To get the currently running application try using Application.Current instead. [MSDN Ref]

Try instead:

Application app = Application.Current;