public override void RangeChanged(SFDateTimeRangeNavigator rangeNavigator, NSDate startDate, NSDate endDate)
        {
            NSDateFormatter resultFormatter = new NSDateFormatter();

            resultFormatter.DateFormat = "MMM dd";

            lblTitle.Text = string.Format(@"Data usage cycle: {0} - {1}",
                                          resultFormatter.ToString(startDate),
                                          resultFormatter.ToString(endDate));

            NSDateFormatter dateFormatter = new NSDateFormatter();

            dateFormatter.DateFormat = @"MMM dd";
            ChartDataModel data = new ChartDataModel();

            NSDate   date;
            NSNumber value;
            int      y = 0;

            for (int i = 0; i < dataPoints.Count; i++)
            {
                data = dataPoints[i];
                date = (CustomizationRangeNavigator.DateTimeToNSDate((DateTime)data.XValue));

                if ((startDate.Compare(date) == NSComparisonResult.Ascending || startDate.Compare(date) == NSComparisonResult.Same) &&
                    (date.Compare(endDate) == NSComparisonResult.Ascending || date.Compare(endDate) == NSComparisonResult.Same))
                {
                    value = (NSNumber)data.YValue;
                    y    += (int)value;
                }
            }

            lblValue.Text = string.Format(@"Data usage - {0} MB", y);
        }
        void Chart_LegendItemCreated(object sender, ChartLegendItemCreatedEventArgs e)
        {
            ChartDataModel dataModel      = e.LegendItem.DataPoint as ChartDataModel;
            float          heightAndWidth = Utility.IsIPad ? 80 : 60;

            UIView legendView = new UIView();

            legendView.Frame = new CGRect(0, 0, 130, heightAndWidth - 10);

            SFChart legendChart = new SFChart();

            legendChart.Frame = new CGRect(0, 0, heightAndWidth, heightAndWidth);

            UIImageView imageView = new UIImageView();

            imageView.Image = UIImage.FromBundle(dataModel.Image);
            imageView.Frame = new CGRect(legendChart.Frame.X / 2, legendChart.Frame.Y / 2, Utility.IsIPad ? 30 : 20, Utility.IsIPad ? 30 : 20);

            SFDoughnutSeries series = new SFDoughnutSeries();

            series.IsStackedDoughnut = true;
            series.Color             = e.LegendItem.IconColor;
            series.ItemsSource       = new List <ChartDataModel>()
            {
                dataModel
            };
            series.XBindingPath        = "XValue";
            series.YBindingPath        = "YValue";
            series.StartAngle          = -90;
            series.EndAngle            = 270;
            series.MaximumValue        = 100;
            series.Spacing             = 0.2;
            series.DoughnutCoefficient = 0.8;
            series.CircularCoefficient = 1.0;
            series.CapStyle            = DoughnutCapStyle.BothCurve;
            series.CenterView          = imageView;
            legendChart.Series.Add(series);
            legendView.AddSubview(legendChart);

            UILabel yLabel = new UILabel();

            yLabel.Frame     = new CGRect(Utility.IsIPad ? 77 : 57, Utility.IsIPad ? 20 : 10, 80, 18);
            yLabel.TextColor = e.LegendItem.IconColor;
            yLabel.Font      = UIFont.FromName("Helvetica", 14f);
            yLabel.Text      = dataModel.YValue.ToString() + "%";

            UILabel xLabel = new UILabel();

            xLabel.Frame     = new CGRect(Utility.IsIPad ? 77 : 57, Utility.IsIPad ? 40 : 30, 80, 18);
            xLabel.TextColor = UIColor.Black;
            xLabel.Font      = UIFont.FromName("Helvetica", 12f);
            xLabel.Text      = dataModel.XValue.ToString();

            legendView.AddSubview(yLabel);
            legendView.AddSubview(xLabel);

            e.LegendItem.View = legendView;
        }
        async void UpdateData()
        {
            await Task.Delay(50);

            if (!isDispose)
            {
                ChartDataModel datapoint = dataModel.dataPointWithTimeInterval(0.13);

                (chart.Series[0].ItemsSource as ObservableCollection <ChartDataModel>).Add(new ChartDataModel(datapoint.XValue, datapoint.YValue));

                if (dataModel.verticalCount < 340)
                {
                    UpdateData();
                }
            }
        }