PromptDialog.Choice - 无效的异常类型

Question

试图利用PromptDialog.Choice当我得到一个无效的类型异常。 这里是我的对话我的代码：

public async Task StartAsync(IDialogContext context) { 
    await context.PostAsync(ConversationHelper.CreateReschedulePromptMessage()); 
    context.Wait(MessageReceivedAsync); 
} 

public virtual async Task MessageReceivedAsync(IDialogContext context, IAwaitable<IMessageActivity> result) { 
    var message = await result; 
    var Options = new[] { "Location", "Date and Time", "Both" }; 

    if (message.Text.ToUpper().CompareTo("PICKUP") == 0) { 
    _rescheduleType = "pickup"; 
    string prompt = string.Format("Is the {0} location incorrect, is the date and time incorrect, or both?", _rescheduleType); 
    PromptDialog.Choice(context, OnResumeFromRescheduleChoice, Options, prompt, promptStyle: PromptStyle.Auto, descriptions: Options); 
    } 
    else if (message.Text.ToUpper().CompareTo("DROP") == 0) { 
    _rescheduleType = "drop-off"; 
    string prompt = string.Format("Is the {0} location incorrect, is the date and time incorrect, or both?", _rescheduleType); 
    PromptDialog.Choice(context, OnResumeFromRescheduleChoice, Options, prompt, promptStyle: PromptStyle.Auto, descriptions: Options); 
    } 
    else { 
    await context.PostAsync(ConversationHelper.CreateGenericRescheduleMessage(SUPPORTNUMBER)); 
    } 

    context.Done<object>(null); 
} 

private async Task OnResumeFromRescheduleChoice(IDialogContext context, IAwaitable<string> result) { 
    var choice = await result; 
} 

的OnResumeFromRescheduleChoice方法烧制，但结果却显示失败，因为ResumeAfter委托期待字符串类型，但接收对象。 PromptDialog的这种不正确的用法？用户也没有被提示选择。我正在使用Bot.Builder版本3.5.5。