Add GradientStops support to GradientBrush

src/Microsoft.MobileBlazorBindings/Elements/GradientBrush.cs

@@ -0,0 +1,16 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+using Microsoft.AspNetCore.Components;
+
+namespace Microsoft.MobileBlazorBindings.Elements
+{
+    public abstract partial class GradientBrush : Brush
+    {
+#pragma warning disable CA1721 // Property names should not match get methods
+        [Parameter] public RenderFragment ChildContent { get; set; }
+#pragma warning restore CA1721 // Property names should not match get methods
+
+        protected override RenderFragment GetChildContent() => ChildContent;
+    }
+}

src/Microsoft.MobileBlazorBindings/Elements/Handlers/GradientBrushHandler.cs

@@ -0,0 +1,50 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+using System;
+using System.Diagnostics;
+using XF = Xamarin.Forms;
+
+namespace Microsoft.MobileBlazorBindings.Elements.Handlers
+{
+    public abstract partial class GradientBrushHandler : BrushHandler, IXamarinFormsContainerElementHandler
+    {
+        public void AddChild(XF.Element child, int physicalSiblingIndex)
+        {
+            if (!(child is XF.GradientStop gradientStopChild))
+            {
+                throw new ArgumentException($"GradientBrush support GradientStop child elements only, but {child?.GetType()} found instead.", nameof(child));
+            }
+
+            if (physicalSiblingIndex <= GradientBrushControl.GradientStops.Count)
+            {
+                GradientBrushControl.GradientStops.Insert(physicalSiblingIndex, gradientStopChild);
+            }
+            else
+            {
+                Debug.WriteLine($"WARNING: {nameof(AddChild)} called with {nameof(physicalSiblingIndex)}={physicalSiblingIndex}, but GradientBrushControl.GradientStops.Count={GradientBrushControl.GradientStops}");
+                GradientBrushControl.GradientStops.Add(gradientStopChild);
+            }
+        }
+
+        public int GetChildIndex(XF.Element child)
+        {
+            if (!(child is XF.GradientStop gradientStopChild))
+            {
+                throw new ArgumentException($"GradientBrush support GradientStop child elements only, but {child?.GetType()} found instead.", nameof(child));
+            }
+
+            return GradientBrushControl.GradientStops.IndexOf(gradientStopChild);
+        }
+
+        public void RemoveChild(XF.Element child)
+        {
+            if (!(child is XF.GradientStop gradientStopChild))
+            {
+                throw new ArgumentException($"GradientBrush support GradientStop child elements only, but {child?.GetType()} found instead.", nameof(child));
+            }
+
+            GradientBrushControl.GradientStops.Remove(gradientStopChild);
+        }
+    }
+}