private void btn_Add_Click(object sender, RoutedEventArgs e)
        {
            GroupBox groupBox = new GroupBox {
                Height = 500, Width = 400
            };
            StackPanel stackPanel = new StackPanel();
            TextBlock  textBlock  = new TextBlock();
            TextBox    textBox    = new TextBox();

            groupBox.Header = "Question #1";
            groupBox.Style  = (Style)groupBox.FindResource("MaterialDesignCardGroupBox");

            textBlock.Text = "TextBlock";



            textBox.Width  = 200;
            textBox.Height = 30;

            stackPanel.Children.Add(textBlock);
            stackPanel.Children.Add(textBox);

            groupBox.Content = stackPanel;

            this.grid.Children.Add(groupBox);
        }