Add Page.ToolbarItems support

samples/ControlGallery/ControlGallery/Views/ShellPropertiesPlayground.razor

@@ -1,30 +1,38 @@
-<ContentPage Title="Shell Properties">
-    <ShellProperties NavBarIsVisible="navBarVisible"
-                     TabBarIsVisible="tabBarVisible"
-                     TitleColor="titleColor" />
+<ContentPage @ref="page">
+    <ToolbarItems>
+        <ToolbarItem Text="Help" OnClick="ShowHelp" />
+    </ToolbarItems>
 
-    <StackLayout>
-        <StackLayout Orientation="StackOrientation.Horizontal">
-            <Label Text="Enable NavBar: " />
-            <CheckBox @bind-IsChecked="navBarVisible" />
+    <ChildContent>
+        <ShellProperties NavBarIsVisible="navBarVisible"
+                         TabBarIsVisible="tabBarVisible"
+                         TitleColor="titleColor" />
+
+        <StackLayout>
+            <StackLayout Orientation="StackOrientation.Horizontal">
+                <Label Text="Enable NavBar: " />
+                <CheckBox @bind-IsChecked="navBarVisible" />
+            </StackLayout>
+            <StackLayout Orientation="StackOrientation.Horizontal">
+                <Label Text="Enable TabBar: " />
+                <CheckBox @bind-IsChecked="tabBarVisible" />
+            </StackLayout>
+            <Button Text="Change Title Color" OnClick="ChangeTitleColor" />
         </StackLayout>
-        <StackLayout Orientation="StackOrientation.Horizontal">
-            <Label Text="Enable TabBar: " />
-            <CheckBox @bind-IsChecked="tabBarVisible" />
-        </StackLayout>
-        <Button Text="Change Title Color" OnClick="ChangeTitleColor" />
-    </StackLayout>
+    </ChildContent>
 </ContentPage>
 
 @code{
+    Microsoft.MobileBlazorBindings.Elements.Page page;
+
     bool navBarVisible = true;
     bool tabBarVisible = true;
     Color? titleColor;
 
     List<Color> colors = new List<Color> {
-        Color.Red,
-        Color.Green,
-        Color.Blue
+    Color.Red,
+    Color.Green,
+    Color.Blue
     };
 
     void ChangeTitleColor()
@@ -32,4 +40,9 @@
         var index = (titleColor.HasValue ? colors.IndexOf(titleColor.Value) + 1 : 0) % colors.Count;
         titleColor = colors[index];
     }
+
+    async Task ShowHelp()
+    {
+        await page.NativeControl.DisplayAlert("Help", "Some help message", "OK");
+    }
 }

src/ComponentWrapperGenerator/TypesToGenerate.txt

@@ -49,6 +49,7 @@ TabbedPage
 TemplatedPage
 TemplatedView
 TimePicker
+ToolbarItem
 View
 VisualElement
 

src/Microsoft.MobileBlazorBindings.Core/ElementHandlerRegistry.cs

@@ -23,6 +23,13 @@ namespace Microsoft.MobileBlazorBindings.Core
             ElementHandlers.Add(typeof(TComponent).FullName, new ElementHandlerFactory((renderer, _) => factory(renderer)));
         }
 
+        public static void RegisterPropertyContentHandler<TComponent>(string propertyName,
+            Func<NativeComponentRenderer, IElementHandler> factory) where TComponent : NativeControlComponentBase
+        {
+            var key = $"p-{typeof(TComponent).FullName}.{propertyName}";
+            ElementHandlers.Add(key, new ElementHandlerFactory((renderer, _) => factory(renderer)));
+        }
+
         public static void RegisterElementHandler<TComponent, TControlHandler>() where TComponent : NativeControlComponentBase where TControlHandler : class, IElementHandler, new()
         {
             RegisterElementHandler<TComponent>((_, __) => new TControlHandler());

src/Microsoft.MobileBlazorBindings.Core/NativeControlComponentBase.cs

@@ -32,6 +32,9 @@ namespace Microsoft.MobileBlazorBindings.Core
                 builder.AddContent(2, childContent);
             }
 
+            int sequence = 3;
+            RenderAdditionalElementContent(builder, ref sequence);
+
             builder.CloseElement();
         }
 
@@ -39,6 +42,10 @@ namespace Microsoft.MobileBlazorBindings.Core
         {
         }
 
+        protected virtual void RenderAdditionalElementContent(RenderTreeBuilder builder, ref int sequence)
+        {
+        }
+
         protected virtual RenderFragment GetChildContent() => null;
     }
 }

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

@@ -0,0 +1,63 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+using Microsoft.MobileBlazorBindings.Core;
+using System;
+using System.Collections.Generic;
+using XF = Xamarin.Forms;
+
+namespace Microsoft.MobileBlazorBindings.Elements.Handlers
+{
+    public class ListContentPropertyHandler<TElementType, TItemType> : IXamarinFormsContainerElementHandler, INonChildContainerElement where TItemType : XF.Element
+    {
+        private readonly Func<TElementType, IList<TItemType>> _listPropertyAccessor;
+        private IList<TItemType> _propertyItems;
+
+        public ListContentPropertyHandler(Func<TElementType, IList<TItemType>> listPropertyAccessor)
+        {
+            _listPropertyAccessor = listPropertyAccessor;
+        }
+
+        public void SetParent(object parentElement)
+        {
+            _propertyItems = _listPropertyAccessor((TElementType)parentElement);
+        }
+
+        void IXamarinFormsContainerElementHandler.AddChild(XF.Element child, int physicalSiblingIndex)
+        {
+            if (!(child is TItemType typedChild))
+            {
+                throw new NotSupportedException($"Cannot add item of type {child?.GetType().Name} to a {typeof(TItemType)} collection.");
+            }
+
+            _propertyItems.Insert(physicalSiblingIndex, typedChild);
+        }
+
+        int IXamarinFormsContainerElementHandler.GetChildIndex(XF.Element child)
+        {
+            return _propertyItems.IndexOf(child as TItemType);
+        }
+
+        void IXamarinFormsContainerElementHandler.RemoveChild(XF.Element child)
+        {
+            _propertyItems.Remove(child as TItemType);
+        }
+
+        // Because this is a 'fake' element, all matters related to physical trees
+        // should be no-ops.
+
+        object IElementHandler.TargetElement => null;
+        void IElementHandler.ApplyAttribute(ulong attributeEventHandlerId, string attributeName, object attributeValue, string attributeEventUpdatesAttributeName) { }
+
+        XF.Element IXamarinFormsElementHandler.ElementControl => null;
+        bool IXamarinFormsElementHandler.IsParented() => false;
+        bool IXamarinFormsElementHandler.IsParentedTo(XF.Element parent) => false;
+
+        void IXamarinFormsElementHandler.SetParent(XF.Element parent)
+        {
+            // This should never get called. Instead, INonChildContainerElement.SetParent() implemented
+            // in this class should get called.
+            throw new NotSupportedException();
+        }
+    }
+}

src/Microsoft.MobileBlazorBindings/Elements/Handlers/ToolbarItemHandler.generated.cs

@@ -0,0 +1,40 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+using Microsoft.MobileBlazorBindings.Core;
+using System;
+using XF = Xamarin.Forms;
+
+namespace Microsoft.MobileBlazorBindings.Elements.Handlers
+{
+    public partial class ToolbarItemHandler : MenuItemHandler
+    {
+
+        public ToolbarItemHandler(NativeComponentRenderer renderer, XF.ToolbarItem toolbarItemControl) : base(renderer, toolbarItemControl)
+        {
+            ToolbarItemControl = toolbarItemControl ?? throw new ArgumentNullException(nameof(toolbarItemControl));
+
+            Initialize(renderer);
+        }
+
+        partial void Initialize(NativeComponentRenderer renderer);
+
+        public XF.ToolbarItem ToolbarItemControl { get; }
+
+        public override void ApplyAttribute(ulong attributeEventHandlerId, string attributeName, object attributeValue, string attributeEventUpdatesAttributeName)
+        {
+            switch (attributeName)
+            {
+                case nameof(XF.ToolbarItem.Order):
+                    ToolbarItemControl.Order = (XF.ToolbarItemOrder)AttributeHelper.GetInt(attributeValue);
+                    break;
+                case nameof(XF.ToolbarItem.Priority):
+                    ToolbarItemControl.Priority = AttributeHelper.GetInt(attributeValue);
+                    break;
+                default:
+                    base.ApplyAttribute(attributeEventHandlerId, attributeName, attributeValue, attributeEventUpdatesAttributeName);
+                    break;
+            }
+        }
+    }
+}

src/Microsoft.MobileBlazorBindings/Elements/Page.cs

@@ -2,12 +2,21 @@
 // Licensed under the MIT license.
 
 using Microsoft.AspNetCore.Components;
+using Microsoft.AspNetCore.Components.Rendering;
 using Microsoft.MobileBlazorBindings.Core;
+using Microsoft.MobileBlazorBindings.Elements.Handlers;
+using XF = Xamarin.Forms;
 
 namespace Microsoft.MobileBlazorBindings.Elements
 {
     public partial class Page : VisualElement
     {
+        static partial void RegisterAdditionalHandlers()
+        {
+            ElementHandlerRegistry.RegisterPropertyContentHandler<Page>(nameof(ToolbarItems),
+                _ => new ListContentPropertyHandler<XF.Page, XF.ToolbarItem>(page => page.ToolbarItems));
+        }
+
         /// <summary>
         /// Indicates that the <see cref="Xamarin.Forms.Page" /> is about to appear.
         /// </summary>
@@ -18,12 +27,19 @@ namespace Microsoft.MobileBlazorBindings.Elements
         /// </summary>
         [Parameter] public EventCallback OnDisappearing { get; set; }
 
+        [Parameter] public RenderFragment ToolbarItems { get; set; }
+
 #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;
 
+        protected override void RenderAdditionalElementContent(RenderTreeBuilder builder, ref int sequence)
+        {
+            RenderTreeBuilderHelper.AddContentProperty(builder, sequence++, typeof(Page), nameof(ToolbarItems), ToolbarItems);
+        }
+
         partial void RenderAdditionalAttributes(AttributesBuilder builder)
         {
             builder.AddAttribute("onappearing", OnAppearing);

src/Microsoft.MobileBlazorBindings/Elements/Page.generated.cs

@@ -15,6 +15,8 @@ namespace Microsoft.MobileBlazorBindings.Elements
         {
             ElementHandlerRegistry.RegisterElementHandler<Page>(
                 renderer => new PageHandler(renderer, new XF.Page()));
+
+            RegisterAdditionalHandlers();
         }
 
         [Parameter] public XF.ImageSource BackgroundImageSource { get; set; }
@@ -66,5 +68,7 @@ namespace Microsoft.MobileBlazorBindings.Elements
         }
 
         partial void RenderAdditionalAttributes(AttributesBuilder builder);
+
+        static partial void RegisterAdditionalHandlers();
     }
 }

src/Microsoft.MobileBlazorBindings/Elements/PropertyWrapperComponent.cs

@@ -0,0 +1,25 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+using Microsoft.AspNetCore.Components;
+using Microsoft.AspNetCore.Components.Rendering;
+using Microsoft.MobileBlazorBindings.Core;
+
+namespace Microsoft.MobileBlazorBindings.Elements
+{
+    /// <summary>
+    /// The only purpose of this type is to wrap content property handler, since currently renderer does not allow 
+    /// handlers without corresponding component.
+    /// </summary>
+#pragma warning disable CA1812 // Avoid uninstantiated internal classes. Class is used generically.
+    internal class PropertyWrapperComponent : NativeControlComponentBase
+#pragma warning restore CA1812 // Avoid uninstantiated internal classes
+    {
+        [Parameter] public RenderFragment ChildContent { get; set; }
+
+        protected override void BuildRenderTree(RenderTreeBuilder builder)
+        {
+            ChildContent(builder);
+        }
+    }
+}

src/Microsoft.MobileBlazorBindings/Elements/ToolbarItem.generated.cs

@@ -0,0 +1,49 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+using Microsoft.AspNetCore.Components;
+using Microsoft.MobileBlazorBindings.Core;
+using Microsoft.MobileBlazorBindings.Elements.Handlers;
+using System.Threading.Tasks;
+using XF = Xamarin.Forms;
+
+namespace Microsoft.MobileBlazorBindings.Elements
+{
+    public partial class ToolbarItem : MenuItem
+    {
+        static ToolbarItem()
+        {
+            ElementHandlerRegistry.RegisterElementHandler<ToolbarItem>(
+                renderer => new ToolbarItemHandler(renderer, new XF.ToolbarItem()));
+        }
+
+        /// <summary>
+        /// Gets or sets a value that indicates on which of the primary, secondary, or default toolbar surfaces to display this <see cref="T:Xamarin.Forms.ToolbarItem" /> element.
+        /// </summary>
+        [Parameter] public XF.ToolbarItemOrder? Order { get; set; }
+        /// <summary>
+        /// Gets or sets the priority of this <see cref="T:Xamarin.Forms.ToolbarItem" /> element.
+        /// </summary>
+        [Parameter] public int? Priority { get; set; }
+
+        public new XF.ToolbarItem NativeControl => ((ToolbarItemHandler)ElementHandler).ToolbarItemControl;
+
+        protected override void RenderAttributes(AttributesBuilder builder)
+        {
+            base.RenderAttributes(builder);
+
+            if (Order != null)
+            {
+                builder.AddAttribute(nameof(Order), (int)Order.Value);
+            }
+            if (Priority != null)
+            {
+                builder.AddAttribute(nameof(Priority), Priority.Value);
+            }
+
+            RenderAdditionalAttributes(builder);
+        }
+
+        partial void RenderAdditionalAttributes(AttributesBuilder builder);
+    }
+}

src/Microsoft.MobileBlazorBindings/RenderTreeBuilderHelper.cs

@@ -0,0 +1,40 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+using Microsoft.AspNetCore.Components;
+using Microsoft.AspNetCore.Components.Rendering;
+using Microsoft.MobileBlazorBindings.Elements;
+using System;
+
+namespace Microsoft.MobileBlazorBindings
+{
+    public static class RenderTreeBuilderHelper
+    {
+        public static void AddContentProperty(RenderTreeBuilder builder, int sequence, Type containingType, string propertyName, RenderFragment content)
+        {
+            if (builder is null)
+            {
+                throw new ArgumentNullException(nameof(builder));
+            }
+
+            if (content != null)
+            {
+                builder.OpenRegion(sequence);
+
+                // Content properties are handled by separate handlers, there rendered as separate child elements.
+                // Renderer does not support elements without parent components as for now,
+                // therefore adding empty parent component to workaround that.
+                builder.OpenComponent<PropertyWrapperComponent>(0);
+                builder.AddAttribute(1, "ChildContent", (RenderFragment)(builder =>
+                {
+                    builder.OpenElement(2, $"p-{containingType.FullName}.{propertyName}");
+                    builder.AddContent(3, content);
+                    builder.CloseElement();
+                }));
+                builder.CloseComponent();
+
+                builder.CloseRegion();
+            }
+        }
+    }
+}