Need help adding points dynamically to a cartesianchart series

[preintel]

After creating a chart with Line series of datetimepoints I want to be able to add single points to the series using INotifyPropertyChanged (of LiveChartsCore.Defaults.DateTimePoint). I am able to create the chart initially however when I use AddItem() method of my viewmodel class it does not update the chart with the new added value.

This is my viewmodel code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using LiveChartsCore;
using LiveChartsCore.Defaults;
using LiveChartsCore.SkiaSharpView;
using System.Collections.ObjectModel;
using System.Windows.Input;

namespace myNamespaceHere
{
    public class ViewModelAuto
    {
        public ObservableCollection<DateTimePoint> _observableValues;

        public ViewModelAuto()
        {
            _observableValues = new ObservableCollection<DateTimePoint> { };

            Series = new ObservableCollection<ISeries>
            {
                new LineSeries<DateTimePoint>
                {
                    Values = _observableValues,
                    Fill = null
                }
            };
        }

        public ObservableCollection<ISeries> Series { get; set; }

        public Axis[] XAxes { get; set; } = new[]
        {
            new Axis
            {
                LabelsRotation = 15,
                Labeler = value => new DateTime((long)value).ToString("yyyy MMM dd"),
                UnitWidth = TimeSpan.FromDays(1).Ticks
            }
        };

        public Axis[] YAxes { get; set; } = new[]
        {
            new Axis
            {
                Labeler = value => "$"+value.ToString(),
                UnitWidth = 1
            }
        };

        public void AddItem(DateTime dtIn, double valueIn)
        {
            _observableValues.Add(new LiveChartsCore.Defaults.DateTimePoint { DateTime = dtIn, Value = valueIn });
        }

    }
}

This is how I am using the ViewModelAuto class on my Winforms cartesianChart object, however the AddItem() method isn't showing the added point on the cartesianChart object when I add the point to the ViewModelAuto class _observableValues object.

ViewModelAuto vm = new ViewModelAuto();
vm.Series = new ObservableCollection<ISeries>
{
new LineSeries<DateTimePoint>
{
 Name = "Series1",
 Values = Series1List
} 
};
cartesianChart1.Series = vm.Series;
vm.AddItem(new DateTimePoint(DateTime.Now, (double)1);  //add a value of 1 for datetime now, this line of code does not call INotifyPropertyChanged on the cartesianchart as it is being called on ViewModelAuto class however I am not sure how to update the chart from here...

[preintel]

Was able to figure out how to use the INotifyProperty to get new data points added without reloading the chart completely:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using LiveChartsCore;
using LiveChartsCore.Defaults;
using LiveChartsCore.SkiaSharpView;
using System.Collections.ObjectModel;
using System.Windows.Input;

using System.ComponentModel;
using System.Drawing;
using System.Runtime.CompilerServices;
using System.Windows.Forms;

namespace MyNamespaceHere
{
    public class ViewModelAuto : INotifyPropertyChanged
    {
        public ObservableCollection<DateTimePoint> _observableValues;
        public event PropertyChangedEventHandler PropertyChanged;
        
        public ObservableCollection<ISeries> _series;

        private void NotifyPropertyChanged([CallerMemberName] String propertyName = "")
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }

        protected virtual void OnPropertyChanged(string propertyName = null)
        {
            //Raise PropertyChanged event
            if (PropertyChanged != null)
                PropertyChanged.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }

        public ViewModelAuto()
        {
            _observableValues = new ObservableCollection<DateTimePoint> { };

            Series = new ObservableCollection<ISeries>
            {
                new LineSeries<DateTimePoint>
                {
                    Values = _observableValues,
                    Fill = null
                }
            };
        }

        public ObservableCollection<ISeries> Series { get { return _series; } set { _series = value; NotifyPropertyChanged("Series"); OnPropertyChanged("Series"); } }

        public ObservableCollection<DateTimePoint> ObservableValues { get { return _observableValues; } set { _observableValues = value; NotifyPropertyChanged("ObservableValues"); OnPropertyChanged("ObservableValues"); } }

        public Axis[] XAxes { get; set; } = new[]
        {
            new Axis
            {
                LabelsRotation = 15,
                Labeler = value => new DateTime((long)value).ToString("yyyy MMM dd"),
                UnitWidth = TimeSpan.FromDays(1).Ticks
            }
        };

        public Axis[] YAxes { get; set; } = new[]
        {
            new Axis
            {
                Labeler = value => "$"+value.ToString(),
                UnitWidth = 1
            }
        };

        public void AddItem(DateTime dtIn, double valueIn)
        {
            _observableValues.Add(new LiveChartsCore.Defaults.DateTimePoint { DateTime = dtIn, Value = valueIn });
            this.ObservableValues = _observableValues;
            this.Series = new ObservableCollection<ISeries>
            {
                new LineSeries<DateTimePoint>
                {
                                                                          Name = "Series Name",
                                                                          Values = this._observableValues
                }
            };
        }

    }
}

Simply load the series:

public ViewModelAuto vm = new ViewModelAuto();
cartesianChart1.Series = vm.Series; //set cartesian chart series

Then to add a value to the chart:

vm.AddItem(DateTime, (double)1); //add a point to the vm Series
cartesianChart.Series = vm.Series; //reassign the vm series to the cartesianchart

[wasilus]

Hello and thank you for the hint to this post. I have been struggling for several days with it, but I am still not able to make it work.
I am a noob!
I tried the above example in WPF.
Where exactly do I need to put these lines

public ViewModelAuto vm = new ViewModelAuto();
cartesianChart1.Series = vm.Series; //set cartesian chart series

Also the name cartesianChart1 does not exist error is given, I do not have that...
Thank you in advance.

[singhacadshravan]

For you help:
https://github.com/beto-rodriguez/LiveCharts2/blob/master/samples/ViewModelsSamples/Lines/AutoUpdate/ViewModel.cs

It is dynamically adding value on the chart without reinitializing "Values". Just maintain a separate List<ObservableCollection> variable(for multiple axis otherwise just ObservableCollection) and update that. Make sure you assign this variable in LineSeries.Values.