private void InitializeFlashCard()
 {
     _flashCardView               = new FlashCardView();
     _flashCardView.Topmost       = true;
     _flashCardView.ShowActivated = false;
     //this.Left
 }
        private void BtnShowAll_Click(object sender, RoutedEventArgs e)
        {
            if (_listFlashCardView == null)
            {
                _listFlashCardView = new List <FlashCardView>();
                var desktopWorkingArea = System.Windows.SystemParameters.WorkArea;

                int    columnNumber     = (int)(desktopWorkingArea.Width / _flashCardView.ActualWidth);
                int    rowNumber        = (int)(desktopWorkingArea.Height / _flashCardView.ActualHeight);
                double leftStartPostion = (desktopWorkingArea.Width - (columnNumber * _flashCardView.ActualWidth)) / 2;
                double topStartPostion  = (desktopWorkingArea.Height - (rowNumber * _flashCardView.ActualHeight)) / 2;

                for (int i = 0; i < rowNumber; i++)
                {
                    for (int j = 0; j < columnNumber; j++)
                    {
                        FlashCardView card = new FlashCardView();
                        card.Owner = this;
                        card.Left  = leftStartPostion + _flashCardView.ActualWidth * j;
                        card.Top   = topStartPostion + _flashCardView.ActualHeight * i;
                        _listFlashCardView.Add(card);
                    }
                }
            }


            foreach (var card in _listFlashCardView)
            {
                card.ShowDialog();
            }
        }