[iOS] Fix CollectionView issue selection multiple items

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue13592.xaml

@@ -0,0 +1,102 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<local:TestContentPage
+    xmlns="http://xamarin.com/schemas/2014/forms"
+    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+    xmlns:d="http://xamarin.com/schemas/2014/forms/design"
+    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    mc:Ignorable="d"
+    Title="Test 13592" xmlns:local="using:Xamarin.Forms.Controls"
+    x:Class="Xamarin.Forms.Controls.Issues.Issue13592">
+    <local:TestContentPage.Resources>
+        <ResourceDictionary>
+
+            <Style TargetType="StackLayout">
+                <Setter Property="VisualStateManager.VisualStateGroups">
+                    <VisualStateGroupList>
+                        <VisualStateGroup x:Name="CommonStates">
+                            <VisualState x:Name="Normal" />
+                            <VisualState x:Name="Selected">
+                                <VisualState.Setters>
+                                    <Setter
+                                        Property="BackgroundColor"
+                                        Value="Yellow" />
+                                </VisualState.Setters>
+                            </VisualState>
+                        </VisualStateGroup>
+                    </VisualStateGroupList>
+                </Setter>
+            </Style>
+
+        </ResourceDictionary>
+    </local:TestContentPage.Resources>
+    <StackLayout>
+        <Label
+            Padding="12"
+            BackgroundColor="Black"
+            TextColor="White"
+            Text="If both CollectionViews have items selected, the test has passed."/>
+    <StackLayout>
+        <StackLayout Orientation="Horizontal">
+            <CollectionView
+                x:Name="stringCollectionView"
+                ItemsSource="{Binding StringItems}"
+                SelectedItems="{Binding SelectedStringItems, Mode=TwoWay}"
+                BackgroundColor="White"
+                ItemSizingStrategy="MeasureFirstItem"
+                SelectionMode="Multiple">
+                <CollectionView.Header>
+                    <Label
+                        Text="String collection:"
+                        BackgroundColor="Gray" />
+                </CollectionView.Header>
+                <CollectionView.ItemTemplate>
+                    <DataTemplate x:DataType="x:String">
+                        <StackLayout>
+                            <Label Text="{Binding .}" />
+                        </StackLayout>
+                    </DataTemplate>
+                </CollectionView.ItemTemplate>
+            </CollectionView>
+            <CollectionView
+                x:Name="intCollectionView"
+                ItemsSource="{Binding IntItems}"
+                SelectedItems="{Binding SelectedIntItems, Mode=TwoWay}"
+                BackgroundColor="White"
+                ItemSizingStrategy="MeasureFirstItem"
+                SelectionMode="Multiple">
+                <CollectionView.Header>
+                    <Label
+                        Text="Int collection:"
+                        BackgroundColor="Gray" />
+                </CollectionView.Header>
+                <CollectionView.ItemTemplate>
+                    <DataTemplate x:DataType="x:Int32">
+                        <StackLayout>
+                            <Label Text="{Binding .}" />
+                        </StackLayout>
+                    </DataTemplate>
+                </CollectionView.ItemTemplate>
+            </CollectionView>
+        </StackLayout>
+        <CollectionView
+            ItemsSource="{Binding Log}"
+            VerticalOptions="End"
+            HeightRequest="200"
+            BackgroundColor="LightGray"
+            ItemsUpdatingScrollMode="KeepLastItemInView">
+            <CollectionView.Header>
+                <Label Text="Log" />
+            </CollectionView.Header>
+            <CollectionView.ItemTemplate>
+                <DataTemplate x:DataType="x:String">
+                    <StackLayout>
+                        <Label
+                            Text="{Binding .}"
+                            FontSize="Small" />
+                    </StackLayout>
+                </DataTemplate>
+            </CollectionView.ItemTemplate>
+        </CollectionView>
+    </StackLayout>
+    </StackLayout>
+</local:TestContentPage>

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue13592.xaml.cs

@@ -0,0 +1,132 @@
+using System.Collections.ObjectModel;
+using System.Linq;
+using System.Windows.Input;
+using Xamarin.Forms.CustomAttributes;
+using Xamarin.Forms.Internals;
+
+#if UITEST
+using Xamarin.UITest;
+using NUnit.Framework;
+using Xamarin.Forms.Core.UITests;
+#endif
+
+namespace Xamarin.Forms.Controls.Issues
+{
+#if UITEST
+	[Category(UITestCategories.CollectionView)]
+#endif
+	[Preserve(AllMembers = true)]
+	[Issue(IssueTracker.Github, 13592,
+		"[Bug] CollectionView initial selection is broken",
+		PlatformAffected.iOS)]
+	public partial class Issue13592 : TestContentPage
+	{
+		public Issue13592()
+		{
+#if APP
+			InitializeComponent();
+            BindingContext = new Issue13592ViewModel();
+#endif
+        }
+
+        protected override void Init()
+		{
+		}
+    }
+
+    public class Issue13592ViewModel : BindableObject
+    {
+        const int NumItems = 20;
+        const int NumSelected = 3;
+
+        ObservableCollection<string> _stringItems;
+        ObservableCollection<object> _selectedStringItems;
+        ObservableCollection<int> _intItems;
+        ObservableCollection<object> _selectedIntItems;
+        ObservableCollection<string> _log;
+
+        public Issue13592ViewModel()
+        {
+            Log = new ObservableCollection<string>();
+
+            IntItems = new ObservableCollection<int>();
+
+            for (var i = 0; i < NumItems; i++)
+                IntItems.Add(i);
+
+            StringItems = new ObservableCollection<string>();
+
+            for (var i = 0; i < NumItems; i++)
+                StringItems.Add(i.ToString());
+
+            AddToLog($"Loaded {NumItems} items");
+
+            SelectedIntItems = new ObservableCollection<object>();
+
+            for (var i = 0; i < NumSelected; i++)
+                SelectedIntItems.Add(i);
+
+            SelectedStringItems = new ObservableCollection<object>();
+
+            for (var i = 0; i < NumSelected; i++)
+                SelectedStringItems.Add(i.ToString());
+
+            AddToLog($"Loaded initial selection of: {string.Join(", ", this.SelectedIntItems)}");
+        }
+
+        public ObservableCollection<string> StringItems
+        {
+            get { return _stringItems; }
+            set
+            {
+                _stringItems = value;
+                OnPropertyChanged();
+            }
+        }
+
+        public ObservableCollection<object> SelectedStringItems
+        {
+            get { return _selectedStringItems; }
+            set
+            {
+                _selectedStringItems = value;
+                OnPropertyChanged();
+            }
+        }
+
+        public ObservableCollection<int> IntItems
+        {
+            get { return _intItems; }
+            set
+            {
+                _intItems = value;
+                OnPropertyChanged();
+            }
+        }
+
+        public ObservableCollection<object> SelectedIntItems
+        {
+            get { return _selectedIntItems; }
+            set
+            {
+                _selectedIntItems = value;
+                OnPropertyChanged();
+            }
+        }
+
+        public ObservableCollection<string> Log
+        {
+            get { return _log; }
+            set
+            {
+                _log = value;
+                OnPropertyChanged();
+            }
+        }
+
+        public void AddToLog(string line)
+        {
+            Log.Add($"{line}.");
+        }
+    }
+}

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems

@@ -1783,6 +1783,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Issue11795.xaml.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue14528.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue14286.xaml.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Issue13592.xaml.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue9079.xaml.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue13588.xaml.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue10101.xaml.cs" />
@@ -2245,6 +2246,9 @@
     <EmbeddedResource Include="$(MSBuildThisFileDirectory)Issue14286.xaml">
       <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
     </EmbeddedResource>
+    <EmbeddedResource Include="$(MSBuildThisFileDirectory)Issue13592.xaml">
+      <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
+    </EmbeddedResource>
     <EmbeddedResource Include="$(MSBuildThisFileDirectory)Issue9079.xaml">
       <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
     </EmbeddedResource>

Xamarin.Forms.Platform.iOS/CollectionView/ItemComparer.cs

@@ -0,0 +1,26 @@
+using System;
+
+namespace Xamarin.Forms.Platform.iOS
+{
+	public static class ItemComparer
+	{
+        public static bool AreEquals(object valueA, object valueB)
+        {
+            bool result;
+            IComparable selfValueComparer;
+
+            selfValueComparer = valueA as IComparable;
+
+            if (valueA == null && valueB != null || valueA != null && valueB == null)
+                result = false;
+            else if (selfValueComparer != null && selfValueComparer.CompareTo(valueB) != 0)
+                result = false;
+            else if (!object.Equals(valueA, valueB))
+                result = false;
+            else
+                result = true; 
+
+            return result;
+        }
+    }
+}

Xamarin.Forms.Platform.iOS/CollectionView/ListSource.cs

@@ -50,7 +50,7 @@ public NSIndexPath GetIndexForItem(object item)
 		{
 			for (int n = 0; n < Count; n++)
 			{
-				if (this[n] == item)
+				if (ItemComparer.AreEquals(this[n], item))
 				{
 					return NSIndexPath.Create(0, n);
 				}

Xamarin.Forms.Platform.iOS/CollectionView/ObservableItemsSource.cs

@@ -71,7 +71,7 @@ public NSIndexPath GetIndexForItem(object item)
 		{
 			for (int n = 0; n < Count; n++)
 			{
-				if (this[n] == item)
+				if(ItemComparer.AreEquals(this[n], item))
 				{
 					return NSIndexPath.Create(_section, n);
 				}

Xamarin.Forms.Platform.iOS/Xamarin.Forms.Platform.iOS.csproj

@@ -279,6 +279,7 @@
     <Compile Include="Renderers\IDisconnectable.cs" />
     <Compile Include="Extensions\BrushExtensions.shared.cs" />
     <Compile Include="Renderers\ShellFlyoutHeaderContainer.cs" />
+    <Compile Include="CollectionView\ItemComparer.cs" />
   </ItemGroup>
   <ItemGroup>
     <EmbeddedResource Include="Resources\StringResources.ar.resx" />