如何在Bot Dialog中处理“后退”？

Question

我有一个对话框要求连续5个附件。 （不是表格，因为AwaitableAttachment尚未发布：How to receive Attachment in Form Dialog?）

我想模仿Form Dialog的“后退”功能，当用户回复“返回”时，我想再次询问上一个问题。我现在正在做的事情有效，但感觉很笨拙。我想知道是否有更好的方法来做到这一点。

我现在拥有的是：

[Serializable]
public class MyDialog : IDialog<string>
{
    private int StateId = 0; //for figuring out which dialog was called, for "going back"

    public async Task StartAsync(IDialogContext context)
    {
        await ReceiveDocument1Async(context);
    }

    private async Task ReceiveDocument1Async(IDialogContext context, IAwaitable<string> result = null)
    {
        StateId = 1;

        if (mustProcessTextMessage(message))
        {
            string message = await result;
            await ProcessTextMessage(context, message);
        }
        else
        {
            string textPrompt = $"Please attach a copy of your **Document1**.";
            context.Call(new ReceiveFileDialog(textPrompt), this.ReceiveDocument2Async);

        }
    }
   ...

    string[] reservedMessages = new string[] { "QUIT", "BACK" };
    string[] separators = new string[] { "|||" };
    private bool mustProcessTextMessage(string message)
    {

        string[] messages = message.Split(separators, StringSplitOptions.None);
        if (reservedMessages.Contains(messages[0]))
            return true;

        return false;
    }

    private async Task ProcessTextMessage(IDialogContext context, string message)
    {

        string[] messages = message.Split(separators, StringSplitOptions.None);


        switch (messages[0])
        {
            case "QUIT":
                context.Done("QUIT");
                break;

            case "BACK":

                StateId -= 1;
                switch (StateId)
                {
                    case 0:
                        context.Done("QUIT");
                        break;
                    case 1:
                        await ReceiveDocument1Async(context);

                        break;
                    case 2:
                        await ReceiveDocument2Async(context);

                        break;
                        ...

                        default:
                        context.Done("QUIT");
                        break;
                }
                break;
            default:
                break;
        }

    }
}