addImage(url: string, container?: Container, selectAction?: CardAction) {
    container = container || this.container;

    const image = new Image();

    image.url = url;
    image.selectAction = selectAction && addCardAction(selectAction);
    image.size = Size.Stretch;

    container.addItem(image);
  }

  addTextBlock(text: string, template: Partial<TextBlock>, container: Container = this.container) {
    if (typeof text !== 'undefined') {
      const textblock = new TextBlock();

      // tslint:disable-next-line:forin
      for (const prop in template) {
        (textblock as any)[prop] = (template as any)[prop];
      }

      textblock.speak = text;
      textblock.text = text;
      container.addItem(textblock);
    }
  }

  addColumnSet(sizes: number[], container: Container = this.container) {
    const columnSet = new ColumnSet();

    container.addItem(columnSet);

    return sizes.map(size => {
      const column = new Column();

      column.width = SizeAndUnit.parse(size);

      columnSet.addColumn(column);

      return column;
    });
  }

 cardElements.forEach(cardElement => container.addItem(cardElement));