private static void ForecastPropertyChangedCallback(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            WeatherItemView weatherItemView = d as WeatherItemView;
            Forecast        f = e.NewValue as Forecast;

            weatherItemView.txtBlkDate.Text        = f.ymd;
            weatherItemView.txtBlkweek.Text        = f.week;
            weatherItemView.LabRiChu.Content       = f.sunrise;
            weatherItemView.LabRiLuo.Content       = f.sunset;
            weatherItemView.txtBlkWeatherType.Text = f.type;
            weatherItemView.labZuiGao.Content      = f.high;
            weatherItemView.labZuiDi.Content       = f.low;
            weatherItemView.LabFengXiang.Content   = f.fx;
            weatherItemView.LabFengLi.Content      = f.fl;
            ChangeImage(weatherItemView, f.type);
        }
        static void ChangeImage(WeatherItemView weatherItemView, string weather)
        {
            switch (weather)
            {
            case "晴":
                weatherItemView.weatherImg.Source = new BitmapImage(new Uri("pack://application:,,,/img/sun.png"));
                break;

            case "多云":
                weatherItemView.weatherImg.Source = new BitmapImage(new Uri("pack://application:,,,/img/duoyun.png"));
                break;

            default:
                break;
            }
        }
        private static void YesterdayPropertyChangedCallback(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            WeatherItemView weatherItemView = d as WeatherItemView;
            Yesterday       Yesterday       = e.NewValue as Yesterday;

            if (Yesterday == null)
            {
                return;
            }
            weatherItemView.txtBlkDate.Text        = Yesterday.ymd;
            weatherItemView.txtBlkweek.Text        = Yesterday.week;
            weatherItemView.LabRiChu.Content       = Yesterday.sunrise;
            weatherItemView.LabRiLuo.Content       = Yesterday.sunset;
            weatherItemView.txtBlkWeatherType.Text = Yesterday.type;
            weatherItemView.labZuiGao.Content      = Yesterday.high;
            weatherItemView.labZuiDi.Content       = Yesterday.low;
            weatherItemView.LabFengXiang.Content   = Yesterday.fx;
            weatherItemView.LabFengLi.Content      = Yesterday.fl;
            ChangeImage(weatherItemView, Yesterday.type);
        }