如何在WebChat中自定义适配卡？

using Microsoft.Bot.Builder;
using Microsoft.Bot.Schema;
using System.Threading;
using System.Threading.Tasks;

public class MyBot : ActivityHandler
{
    protected override async Task OnMessageActivityAsync(ITurnContext<IMessageActivity> turnContext, CancellationToken cancellationToken)
    {
        // 处理用户消息
        var userMessage = turnContext.Activity.Text;

        // 创建适配卡
        var card = new HeroCard
        {
            Title = "自定义适配卡",
            Text = "这是一个自定义适配卡的示例",
            Images = new List<CardImage> { new CardImage("https://example.com/image.jpg") },
            Buttons = new List<CardAction> { new CardAction(ActionTypes.OpenUrl, "了解更多", value: "https://example.com") }
        };

        // 创建适配卡响应
        var response = MessageFactory.Attachment(card.ToAttachment());

        // 发送适配卡响应
        await turnContext.SendActivityAsync(response, cancellationToken);
    }
}

public class Startup
{
    public void ConfigureServices(IServiceCollection services)
    {
        // 注册适配器
        services.AddSingleton<IBotFrameworkHttpAdapter, BotFrameworkHttpAdapter>();

        // 注册机器人
        services.AddSingleton<MyBot>();
    }
}