public static void Initialize(IntPtr handle)
{
if (Instance != null)
{
throw new InvalidOperationException("WindowCollection already initialized.");
}
WindowCollection windowCollection = new WindowCollection(handle);
_instance = windowCollection;
}
void MainWindowLoaded(object sender, RoutedEventArgs e)
{
IntPtr intPtr = new WindowInteropHelper(this).Handle;
WindowCollection.Initialize(intPtr);
}