Most Efficient Way for getting notified on window open

Question

I am writing an app (C# and WPF in .NET 4.0) that needs to get open windows and close them if they are not in it\'s white-list.

So far, using EnumDesktopWindo

Answer 1

Use the System.Windows.Automation namespace.

Example (taken from The Old New Thing) which waits for a specific process to open a dialog box, then dismisses it:

using System;
using System.Windows.Automation;
using System.Diagnostics;
using System.Threading;

class Program
{
    [STAThread]
    public static void Main(string[] args)
    {     
        Automation.AddAutomationEventHandler(
            WindowPattern.WindowOpenedEvent,
            AutomationElement.RootElement,
            TreeScope.Children,
            (sender, e) =>
            {
                var element = sender as AutomationElement;

                Console.WriteLine("new window opened");
            });

        Console.ReadLine();

        Automation.RemoveAllEventHandlers();
    }
}