Botframework 如何在composer自定义操作中使用Bottate

//尝试像这样初始化状态，但它始终为空

有人知道如何在composer自定义操作中保存状态吗

private ConversationState _conversationState;
        private UserState _userState;
        BotState _botstate;
   
    [JsonConstructor]
    public MultiplyDialog(ConversationState conversationState, UserState userState, [CallerFilePath] string sourceFilePath = "", [CallerLineNumber] int sourceLineNumber = 0)
        : base()
    {
        // enable instances of this command as debug break point
        _conversationState = conversationState;//always null
        _userState = userState;
        this.RegisterSourceLocation(sourceFilePath, sourceLineNumber);
    }