private void initialiseSize()
        {
            int smallCount  = context.orders.Where(e => e.size.Equals("Small")).Count();
            int mediumCount = context.orders.Where(e => e.size.Equals("Medium")).Count();
            int larkeCount  = context.orders.Where(e => e.size.Equals("Large")).Count();

            SizeCollection.Clear();
            SizeCollection.Add(new PieSeries
            {
                Title  = Application.Current.FindResource("Small") as string,
                Values = new ChartValues <ObservableValue> {
                    new ObservableValue(smallCount)
                },
                DataLabels = true
            });
            SizeCollection.Add(new PieSeries
            {
                Title  = Application.Current.FindResource("Medium") as string,
                Values = new ChartValues <ObservableValue> {
                    new ObservableValue(mediumCount)
                },
                DataLabels = true
            });
            SizeCollection.Add(new PieSeries
            {
                Title  = Application.Current.FindResource("Large") as string,
                Values = new ChartValues <ObservableValue> {
                    new ObservableValue(larkeCount)
                },
                DataLabels = true
            });
        }