Fix 1422

src/LiveChartsCore/CartesianChart.cs

@@ -101,7 +101,7 @@ public CartesianChart(
 
     ///<inheritdoc cref="Chart{TDrawingContext}.Series"/>
     public override IEnumerable<IChartSeries<TDrawingContext>> Series =>
-        _chartView.Series.Cast<IChartSeries<TDrawingContext>>();
+        _chartView.Series?.Cast<IChartSeries<TDrawingContext>>() ?? [];
 
     ///<inheritdoc cref="Chart{TDrawingContext}.VisibleSeries"/>
     public override IEnumerable<IChartSeries<TDrawingContext>> VisibleSeries =>
@@ -403,8 +403,20 @@ protected internal override void Measure()
         var viewDrawMargin = _chartView.DrawMargin;
         ControlSize = _chartView.ControlSize;
 
-        YAxes = _chartView.YAxes.Cast<ICartesianAxis<TDrawingContext>>().ToArray();
-        XAxes = _chartView.XAxes.Cast<ICartesianAxis<TDrawingContext>>().ToArray();
+        var x = _chartView.XAxes;
+        var y = _chartView.YAxes;
+
+        if (x is null || y is null)
+        {
+            // in theory nulls are not valid, see ChartTest.cs for more context.
+            var provider = LiveCharts.DefaultSettings.GetProvider<TDrawingContext>();
+
+            x = [provider.GetDefaultCartesianAxis()];
+            y = [provider.GetDefaultCartesianAxis()];
+        }
+
+        XAxes = x.Cast<ICartesianAxis<TDrawingContext>>().ToArray();
+        YAxes = y.Cast<ICartesianAxis<TDrawingContext>>().ToArray();
 
         if (XAxes.Length == 0 || YAxes.Length == 0)
         {

src/LiveChartsCore/PieChart.cs

@@ -53,7 +53,7 @@ public class PieChart<TDrawingContext>(
 
     ///<inheritdoc cref="Chart{TDrawingContext}.Series"/>
     public override IEnumerable<IChartSeries<TDrawingContext>> Series =>
-        view.Series.Cast<IChartSeries<TDrawingContext>>();
+        view.Series?.Cast<IChartSeries<TDrawingContext>>() ?? [];
 
     ///<inheritdoc cref="Chart{TDrawingContext}.VisibleSeries"/>
     public override IEnumerable<IChartSeries<TDrawingContext>> VisibleSeries =>

src/LiveChartsCore/PolarChart.cs

@@ -69,7 +69,7 @@ public class PolarChart<TDrawingContext>(
 
     ///<inheritdoc cref="Chart{TDrawingContext}.Series"/>
     public override IEnumerable<IChartSeries<TDrawingContext>> Series =>
-        view.Series.Cast<IChartSeries<TDrawingContext>>();
+        view.Series?.Cast<IChartSeries<TDrawingContext>>() ?? [];
 
     ///<inheritdoc cref="Chart{TDrawingContext}.VisibleSeries"/>
     public override IEnumerable<IChartSeries<TDrawingContext>> VisibleSeries =>
@@ -157,8 +157,25 @@ protected internal override void Measure()
         var viewDrawMargin = view.DrawMargin;
         ControlSize = view.ControlSize;
 
-        AngleAxes = view.AngleAxes.Cast<IPolarAxis>().ToArray();
-        RadiusAxes = view.RadiusAxes.Cast<IPolarAxis>().ToArray();
+        var a = view.AngleAxes;
+        var r = view.RadiusAxes;
+
+        if (a is null || r is null)
+        {
+            // in theory nulls are not valid, see ChartTest.cs for more context.
+            var provider = LiveCharts.DefaultSettings.GetProvider<TDrawingContext>();
+
+            a = [provider.GetDefaultPolarAxis()];
+            r = [provider.GetDefaultPolarAxis()];
+        }
+
+        AngleAxes = a.Cast<IPolarAxis>().ToArray();
+        RadiusAxes = r.Cast<IPolarAxis>().ToArray();
+
+        if (AngleAxes.Length == 0 || RadiusAxes.Length == 0)
+        {
+            throw new Exception($"{nameof(AngleAxes)} and {nameof(RadiusAxes)} must contain at least one element.");
+        }
 
         var theme = LiveCharts.DefaultSettings.GetTheme<TDrawingContext>();
 

tests/LiveChartsCore.UnitTesting/ChartTests/ChartTests.cs

@@ -0,0 +1,96 @@
+// The MIT License(MIT)
+//
+// Copyright(c) 2021 Alberto Rodriguez Orozco & LiveCharts Contributors
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+using System.Net.NetworkInformation;
+using LiveChartsCore.SkiaSharpView.SKCharts;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace LiveChartsCore.UnitTesting.ChartTests;
+
+[TestClass]
+public class ChartTests
+{
+    // based on https://github.com/beto-rodriguez/LiveCharts2/issues/1422
+
+    // in theory LiveCharts properties should never be null, but we can't control the user input
+    // specially on this case where DataContext could be null
+
+    [TestMethod]
+    public void CartesianShouldHandleNullParams()
+    {
+        // we are testing the properties defined on LiveChartsCore/Kernel/Sketches/ICartesianChartView.cs
+
+        var chart = new SKCartesianChart
+        {
+            Width = 1000,
+            Height = 1000,
+            XAxes = null,
+            YAxes = null,
+            Sections = null,
+            Series = null,
+            DrawMarginFrame = null,
+            VisualElements = null
+        };
+
+        var image = chart.GetImage();
+
+        Assert.IsTrue(image is not null);
+    }
+
+    [TestMethod]
+    public void PieShouldHandleNullParams()
+    {
+        // we are testing the properties defined on LiveChartsCore/Kernel/Sketches/IPieChartView.cs
+
+        var chart = new SKPieChart
+        {
+            Width = 1000,
+            Height = 1000,
+            Series = null,
+            VisualElements = null
+        };
+
+        var image = chart.GetImage();
+
+        Assert.IsTrue(image is not null);
+    }
+
+    [TestMethod]
+    public void PolarShouldHandleNullParams()
+    {
+        // we are testing the properties defined on LiveChartsCore/Kernel/Sketches/IPolarChartView.cs
+
+        var chart = new SKPolarChart
+        {
+            Width = 1000,
+            Height = 1000,
+            Series = null,
+            AngleAxes = null,
+            RadiusAxes = null,
+            VisualElements = null
+        };
+
+        var image = chart.GetImage();
+
+        Assert.IsTrue(image is not null);
+    }
+}