Basic Area

View model

using CommunityToolkit.Mvvm.ComponentModel;
using LiveChartsCore;
using LiveChartsCore.SkiaSharpView;
using LiveChartsCore.SkiaSharpView.Painting;
using SkiaSharp;

namespace ViewModelsSamples.Lines.Area;

public partial class ViewModel : ObservableObject
{
    public ISeries[] Series { get; set; } =
    {
        new LineSeries<double>
        {
            Values = new double[] { -2, -1, 3, 5, 3, 4, 6 },
            // Set he Fill property to build an area series
            // by default the series has a fill color based on your app theme
            Fill = new SolidColorPaint(SKColors.CornflowerBlue), // mark

            Stroke = null,
            GeometryFill = null,
            GeometryStroke = null
        }
    };

    // Creates a gray background and border in the draw margin.
    public DrawMarginFrame DrawMarginFrame => new()
    {
        Fill = new SolidColorPaint(new SKColor(220, 220, 220)),
        Stroke = new SolidColorPaint(new SKColor(180, 180, 180), 1)
    };
}

Form code behind

using System.Windows.Forms;
using LiveChartsCore.SkiaSharpView.WinForms;
using ViewModelsSamples.Lines.Area;

namespace WinFormsSample.Lines.Area;

public partial class View : UserControl
{
    private readonly CartesianChart cartesianChart;

    public View()
    {
        InitializeComponent();
        Size = new System.Drawing.Size(50, 50);

        var viewModel = new ViewModel();

        cartesianChart = new CartesianChart
        {
            Series = viewModel.Series,
            DrawMarginFrame = viewModel.DrawMarginFrame,

            // out of livecharts properties...
            Location = new System.Drawing.Point(0, 0),
            Size = new System.Drawing.Size(50, 50),
            Anchor = AnchorStyles.Left | AnchorStyles.Right | AnchorStyles.Top | AnchorStyles.Bottom
        };

        Controls.Add(cartesianChart);
    }
}

Articles you might also find useful: