Question

我不知道为什么会出现未定义的错误。这是我收到的错误消息：＆＃34; TypeError：无法设置属性＆＃39; state＆＃39;未定义＆＃34;

这是我的代码：

export class MobileMenuComponent implements OnInit {

menu: any;

constructor() { 


}

ngOnInit() { 

    this.menu.state = 'inactive';

    this.menu.togglemenu = function() {

        if (this.menu.state === 'inactive'){

            this.menu.state = 'active';

        }

        else {

            this.menu.state = 'inactive';

        }

    }

}


}

Answer 1

在构造函数中将this.menu定义为空对象，它将起作用。

Answer 2

   private async void _timer_Tick(object sender, object e)
    {
        DhtReading reading = new DhtReading();
        int val = this.TotalAttempts;
        this.TotalAttempts++;

        reading = await _dht.GetReadingAsync().AsTask();

        _retryCount.Add(reading.RetryCount);
        this.OnPropertyChanged(nameof(AverageRetriesDisplay));
        this.OnPropertyChanged(nameof(TotalAttempts));
        this.OnPropertyChanged(nameof(PercentSuccess));

        if (reading.IsValid)
        {
            this.TotalSuccess++;
            this.Temperature = Convert.ToSingle(reading.Temperature);
            this.Humidity = Convert.ToSingle(reading.Humidity);
            this.LastUpdated = DateTimeOffset.Now;
            this.OnPropertyChanged(nameof(SuccessRate));

            //Inserir aqui o método de gravação de arquivo.

                StreamWriter SW;
                SW = File.AppendText(@"Arquivo.txt");
                SW.WriteLine("Evento Gerado em: " + DateTime.Now.ToString() + Humidity + Temperature + "\n\r");
        SW.Close();
    }
}

函数内的

this - 用于函数本身，它不包含菜单成员。你应该使用内部togglemenu内部函数。像这样：

this

未定义的错误Angular 2类

2 个答案: