如何在MS bot框架中从IDialog.StartAsync()中发布丰富内容

using Microsoft.Bot.Builder.Dialogs;
using Microsoft.Bot.Connector;
using System;
using System.Threading.Tasks;

[Serializable]
public class RichContentDialog : IDialog<object>
{
    public async Task StartAsync(IDialogContext context)
    {
        // 创建一个HeroCard
        var heroCard = new HeroCard
        {
            Title = "标题",
            Subtitle = "副标题",
            Text = "这是一个HeroCard示例",
            Images = new List<CardImage> { new CardImage("图片URL") },
            Buttons = new List<CardAction> { new CardAction(ActionTypes.OpenUrl, "按钮标题", value: "按钮URL") }
        };

        // 创建一个ThumbnailCard
        var thumbnailCard = new ThumbnailCard
        {
            Title = "标题",
            Subtitle = "副标题",
            Text = "这是一个ThumbnailCard示例",
            Images = new List<CardImage> { new CardImage("图片URL") },
            Buttons = new List<CardAction> { new CardAction(ActionTypes.OpenUrl, "按钮标题", value: "按钮URL") }
        };

        // 创建一个ReceiptCard
        var receiptCard = new ReceiptCard
        {
            Title = "标题",
            Facts = new List<Fact> { new Fact("Fact1", "Value1"), new Fact("Fact2", "Value2") },
            Items = new List<ReceiptItem> { new ReceiptItem("Item1", price: "10.00", quantity: "2", image: new CardImage("图片URL")) },
            Total = "20.00"
        };

        // 将卡片添加到消息队列中
        var message = context.MakeMessage();
        message.Attachments.Add(heroCard.ToAttachment());
        message.Attachments.Add(thumbnailCard.ToAttachment());
        message.Attachments.Add(receiptCard.ToAttachment());

        // 发送消息给用户
        await context.PostAsync(message);

        // 结束对话
        context.Done<object>(null);
    }
}