Real-time XamDataChart | Infragistics Forums

The Code Behind:

public partial class MainPage : UserControl
    {
        private Random _rand = new Random();
        private DispatcherTimer _timer = new DispatcherTimer();
        private double _curr = 0.0;
        //private TestData _td = new TestData();

        private RealTimeDataBuffer _td = new RealTimeDataBuffer() { HistoryTimeSpan = new TimeSpan(0, 1, 0) };

        public MainPage()
        {
            InitializeComponent();

            DataContext = _td;
            _timer.Interval = new TimeSpan(0, 0, 0, 0, 100);
            _timer.Tick += Timer_Tick;
            _timer.Start();
        }

        TimeSpan max = new TimeSpan(0, 1, 0);
        List<TestDataItem> _bufferedData = new List<TestDataItem>();

        void Timer_Tick(object sender, EventArgs e)
        {
            if (_rand.NextDouble() > .5)
            {
                _curr += _rand.NextDouble();
            }
            else
            {
                _curr -= _rand.NextDouble();
            }
            _bufferedData.Add(
                new TestDataItem()
                {
                    TimeStamp = DateTime.Now,
                    Value = _curr
                });

            // Add the data to the chart in groups of 10
            if (_bufferedData.Count >= 10)
            {
                _td.Add(_bufferedData);
                _bufferedData.Clear();
            }
        }
    }

    //public class TestData
    //    : ObservableCollection<TestDataItem>
    //{
    //}

    public class TestDataItem
    {
        public DateTime TimeStamp { get; set; }
        public double Value { get; set; }
    }

    public class RealTimeDataBuffer : DependencyObject, INotifyCollectionChanged, IEnumerable
    {
        public event NotifyCollectionChangedEventHandler CollectionChanged;

        private List<TestDataItem> historicalDataSource = new List<TestDataItem>();
        private TimeSpan dataPointInterval;

        public TimeSpan HistoryTimeSpan
        {
            get { return dataPointInterval; }
            set { dataPointInterval = value; }
        }

        public IEnumerator GetEnumerator()
        {
            return historicalDataSource.GetEnumerator();
        }

        /// <summary>
        /// Add a specified number of records from
        /// historical dataset to dataset
        /// </summary>
        /// <param name="recordCount"></param>
        public void Add(IEnumerable<TestDataItem> items)
        {
            foreach (var item in items) historicalDataSource.Add(item);

            // Remove any old data
            DateTime minTime = historicalDataSource.Last().TimeStamp - dataPointInterval;
            while (historicalDataSource.First().TimeStamp < minTime)
            {
                // Remove this item from the total
                historicalDataSource.RemoveAt(0);
            }

            if (CollectionChanged != null)
            {
                CollectionChanged(this, new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
            }
        }
    }

if (CollectionChanged != null) { CollectionChanged(this, new NotifyCollectionChangedEventArgs( NotifyCollectionChangedAction.Reset)); int lastIndex = historicalDataSource.Count - 1; CollectionChanged(this, new NotifyCollectionChangedEventArgs( NotifyCollectionChangedAction.Remove, historicalDataSource[lastIndex - 1], lastIndex)); CollectionChanged(this, new NotifyCollectionChangedEventArgs( NotifyCollectionChangedAction.Add, historicalDataSource[lastIndex - 1], lastIndex)); }