区分是否使用Microsoft Bot Framework中的context.Call（）或context.Forward（）调用IDialog

Question

I have a subdialog in a bot built using MS bot framework that starts as follows - the standard way:

    public async Task StartAsync(IDialogContext context)
    {
        var msg = "Let's find your flights! Tell me the flight number, city or airline.";
        var reply = context.MakeMessage();
        reply.Text = msg;
        //add quick replies here
        await context.PostAsync(reply);
        context.Wait(UserInputReceived);
    }

This dialog is called using two different ways, depending on whether in the previous screen the user tapped a button that says "Flights" or immediately entered a flight number. Here is the code from the parent dialog:

else if (response.Text == MainOptions[2]) //user tapped a button
{
    context.Call(new FlightsDialog(), ChildDialogComplete);
}
else //user entered some text instead of tapping a button
{
    await context.Forward(new FlightsDialog(), ChildDialogComplete,
                          activity, CancellationToken.None);
}

Question : how can I know (from within the FlightsDialog ) whether that dialog was called using context.Call() or context.Forward() ? This is because in the case of context.Forward() , StartAsync() shouldn't output the prompt asking the user to enter the flight number - they already did this.

The best idea I have is to save a flag in the ConversationData or user data, as below, and access it from the IDialog, but I thought there could be a better way?

public static void SetUserDataProperty(Activity activity, string PropertyName, string ValueToSet)
{
    StateClient client = activity.GetStateClient();
    BotData userData = client.BotState.GetUserData(activity.ChannelId, activity.From.Id);
    userData.SetProperty<string>(PropertyName, ValueToSet);
    client.BotState.SetUserDataAsync(activity.ChannelId, activity.From.Id, userData);
}

Answer 1

Unfortunately Forward actually calls Call (and then does some other stuff afterwards), so your Dialog wouldn't be able to differentiate.

void IDialogStack.Call<R>(IDialog<R> child, ResumeAfter<R> resume)
{
    var callRest = ToRest(child.StartAsync);
    if (resume != null)
    {
        var doneRest = ToRest(resume);
        this.wait = this.fiber.Call<DialogTask, object, R>(callRest, null, doneRest);
    }
    else
    {
        this.wait = this.fiber.Call<DialogTask, object>(callRest, null);
    }
}

async Task IDialogStack.Forward<R, T>(IDialog<R> child, ResumeAfter<R> resume, T item, CancellationToken token)
{
    IDialogStack stack = this;
    stack.Call(child, resume);
    await stack.PollAsync(token);
    IPostToBot postToBot = this;
    await postToBot.PostAsync(item, token);
}

From https://github.com/Microsoft/BotBuilder/blob/10893730134135dd4af4250277de8e1b980f81c9/CSharp/Library/Dialogs/DialogTask.cs#L196