//Add an existing word.
        private void Lb_PreviewMouseDown(object sender, MouseButtonEventArgs e)
        {
            string data = (sender as Label).Content.ToString();

            try
            {
                data = (sender as Label).Content.ToString().Split(" 1234567890.,!?()-_<>';:\"\\/=+-/^@$%{}|&\n\r\t".ToCharArray(), StringSplitOptions.RemoveEmptyEntries)[0];
            }
            catch
            {
                return;
            }
            int?word = _proxy.GetWord(data);

            if (word == null)
            {
                AddWord form = new AddWord(_proxy, data, user, videoId, ServerData.Video);
                _play = true;
                btnPlay_Click(null, null);
                form.ShowDialog();
                btnPlay_Click(null, null);
            }
            else
            {
                _play = true;
                btnPlay_Click(null, null);
                if (MessageBox.Show("Do you want to add this word to your list?", "Save word", MessageBoxButton.YesNo, MessageBoxImage.Question) == MessageBoxResult.Yes)
                {
                    _proxy.AddItemsWord(Convert.ToInt32(word), videoId, ServerData.Video);
                    _proxy.AddItemsWord(Convert.ToInt32(word), Convert.ToInt32(user), ServerData.User);
                }
                btnPlay_Click(null, null);
            }
        }
        //Add a new word.
        private void Lb_PreviewMouseDown(object sender, MouseButtonEventArgs e)
        {
            string data = (sender as TextBox).Text;

            try
            {
                data = (sender as TextBox).Text.Split(" 1234567890.,!'?()-_<>;:\"\\/=+-/^@$%{}|&\n\r\t".ToCharArray(), StringSplitOptions.RemoveEmptyEntries)[0];
            }
            catch
            {
                return;
            }
            int?word = _proxy.GetWord(data);

            if (word == null)
            {
                AddWord form = new AddWord(_proxy, data, user, book, ServerData.Book);
                form.ShowDialog();
            }
            else
            {
                if (MessageBox.Show("Do you want to add this word to your list?", "Save word", MessageBoxButton.YesNo, MessageBoxImage.Question) == MessageBoxResult.Yes)
                {
                    _proxy.AddItemsWord(Convert.ToInt32(word), book, ServerData.Book);
                    _proxy.AddItemsWord(Convert.ToInt32(word), user, ServerData.User);
                }
            }
        }
        //Show a form for editting the word.
        private void btnEditWord_Click(object sender, RoutedEventArgs e)
        {
            AddWord form = new AddWord(_proxy, Convert.ToInt32((sender as Button).Tag), Convert.ToInt32(_proxy.GetItemsId(lUserName.Content.ToString(), ServerData.User)));

            form.ShowDialog();
            btnWords_Click(null, null);
        }
        //Show a form for adding a new word.
        private void btnAddWord(object sender, RoutedEventArgs e)
        {
            int?    user = _proxy.GetItemsId(lUserName.Content.ToString(), ServerData.User);
            AddWord form = new AddWord(_proxy, user);

            form.ShowDialog();
            btnWords_Click(null, null);
        }