如何在 Microsoft Bot Framework 中的对话框之间传递对象？

Question

我正在尝试IList<Attachment>在 Bot Framework 中的两个对话框之间传递一个类型的对象。这是我的代码现在的样子：

主对话框：

[Serializable]
public class CarouselCardsDialog : IDialog<object>
{
    public async Task StartAsync(IDialogContext context)
    {
        context.Wait(this.MessageReceivedAsync);
    }

    public virtual async Task MessageReceivedAsync(IDialogContext context, IAwaitable<IMessageActivity> result)
    {
        //This object, 'attachments' is what I need to pass to the child dialog.
        IList<Attachment> attachments = GetCardsAttachments();
        context.Call(new CarouselDialog(attachments), ResumeAfterPrompt);
    }

    private async Task ResumeAfterPrompt(IDialogContext context, IAwaitable<string> result)
    {
        string input = await result;
        await context.PostAsync(input);
        context.Wait(MessageReceivedAsync);
    }

    private static IList<Attachment> GetCardsAttachments()
    {
        //Get a list of attachment
    }
}

这是子对话框。我想将 CarouselCardsDialog 中的附件列表传递给这个对象：

[Serializable]
public class CarouselDialog : IDialog<string>
{
    private IList<Attachment> _attachments;

    public CarouselDialog(IList<Attachment> attachments)
    {
        _attachments = attachments;
    }

    public async Task StartAsync(IDialogContext context)
    {
        IMessageActivity reply = context.MakeMessage();
        reply.AttachmentLayout = AttachmentLayoutTypes.Carousel;
        reply.Attachments = _attachments;
        await context.PostAsync(reply);
        context.Wait(MessageReceivedAsync);
    }

    public virtual async Task MessageReceivedAsync(IDialogContext context, IAwaitable<IMessageActivity> result)
    {
        IMessageActivity activity = await result;
        context.Done(activity.Text);
    }
}

但是，当我运行此代码时，出现此错误：

例外：程序集“Microsoft.Bot.Connector, Version=3.5.1.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35”中的类型“Microsoft.Bot.Connector.Attachment”未标记为可序列化。

我究竟做错了什么？有没有解决的办法？

Answer 1

不确定异常，但解决方法是为制作附件所需的所有数据创建模型，然后将此数据保存在上下文的 UserData 属性中。

context.UserData.SetValue<MyModel>("AttachmentsModel", instanceOfModel);

然后在你的第二个对话框中检索这个模型

MyModel model;
context.UserData.TryGetValue<MyModel>("AttachmentsModel", out model);

我认为您也可以尝试在此属性中放置一个 IAttachment 对象，但模型会更好，因为它并不是真正用于容纳大型对象。