updating Sandbox app to follow better MVVM patterns

Sandbox/Windows10/HelloWorld/HelloWorld.Unity/App.xaml.cs

@@ -4,6 +4,7 @@
 using Prism.Unity;
 using Sample.ViewModels;
 using Sample.Views;
+using SampleData.StarTrek;
 using System;
 using System.Collections.Generic;
 using System.IO;
@@ -32,6 +33,7 @@ public App()
 
         protected override void RegisterTypes(IContainerRegistry container)
         {
+            container.RegisterSingleton<IDatabase, Database>();
             container.RegisterForNavigation<MainPage, MainPageViewModel>();
             container.RegisterForNavigation<ItemPage, ItemPageViewModel>();
         }

Sandbox/Windows10/HelloWorld/HelloWorld.Unity/Converters/ItemClickedConverter.cs

@@ -0,0 +1,22 @@
+using System;
+using Windows.UI.Xaml.Controls;
+using Windows.UI.Xaml.Data;
+
+namespace HelloWorld.Converters
+{
+    public class ItemClickedConverter : IValueConverter
+    {
+        public object Convert(object value, Type targetType, object parameter, string language)
+        {
+            if (value is ItemClickEventArgs args)
+                return args.ClickedItem;
+
+            return null;
+        }
+
+        public object ConvertBack(object value, Type targetType, object parameter, string language)
+        {
+            throw new NotImplementedException();
+        }
+    }
+}

Sandbox/Windows10/HelloWorld/HelloWorld.Unity/HelloWorld.Unity.csproj

@@ -95,6 +95,7 @@
       <DependentUpon>App.xaml</DependentUpon>
     </Compile>
     <Compile Include="Controls\AppBarLiteral.cs" />
+    <Compile Include="Converters\ItemClickedConverter.cs" />
     <Compile Include="Models\GroupedMembers.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="ViewModels\ItemPageViewModel.cs" />
@@ -147,6 +148,9 @@
     <PackageReference Include="Microsoft.NETCore.UniversalWindowsPlatform">
       <Version>6.1.9</Version>
     </PackageReference>
+    <PackageReference Include="Microsoft.Xaml.Behaviors.Uwp.Managed">
+      <Version>2.0.0</Version>
+    </PackageReference>
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\..\..\Source\Prism\Prism.csproj">

Sandbox/Windows10/HelloWorld/HelloWorld.Unity/ViewModels/ItemPageViewModel.cs

@@ -1,4 +1,5 @@
-using Prism.Mvvm;
+using Prism.Commands;
+using Prism.Mvvm;
 using Prism.Navigation;
 using SampleData.StarTrek;
 using Windows.UI.Xaml.Media.Animation;
@@ -7,25 +8,17 @@ namespace Sample.ViewModels
 {
     internal class ItemPageViewModel : BindableBase, INavigatedAware
     {
-        private INavigationService _nav;
+        private INavigationService _navigationService { get; }
 
-        public ItemPageViewModel()
+        public ItemPageViewModel(INavigationService navigationService)
         {
-            // empty
+            _navigationService = navigationService;
+            GoBackCommand = new DelegateCommand(OnGoBackCommandExecuted);
         }
 
         public void OnNavigatedTo(INavigationParameters parameters)
         {
-            _nav = parameters.GetNavigationService();
-            if (parameters.TryGetValue<string>(nameof(Member), out var parameter))
-            {
-                if (Member.TryFromJson(parameter, out var member))
-                {
-                    Member = member;
-                }
-                else { /* invalid parameter */ }
-            }
-            else { /* missing parameter */ }
+            Member = parameters.GetValue<Member>("member");
         }
 
         public void OnNavigatedFrom(INavigationParameters parameters)
@@ -40,9 +33,11 @@ public Member Member
             set => SetProperty(ref _member, value);
         }
 
-        public async void GoBack()
+        public DelegateCommand GoBackCommand { get; }
+
+        private async void OnGoBackCommandExecuted()
         {
-            await _nav.GoBackAsync();
+            await _navigationService.GoBackAsync();
         }
     }
 }

Sandbox/Windows10/HelloWorld/HelloWorld.Unity/ViewModels/MainPageViewModel.cs

@@ -1,40 +1,33 @@
-using Prism.Mvvm;
+using Prism.Commands;
+using Prism.Mvvm;
 using Prism.Navigation;
 using Sample.Models;
 using SampleData.StarTrek;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
+using System.Diagnostics;
 using System.Linq;
 using System.Threading.Tasks;
+using Windows.UI.Xaml.Controls;
 using Windows.UI.Xaml.Media.Animation;
 
 namespace Sample.ViewModels
 {
     class MainPageViewModel : BindableBase, INavigatedAwareAsync
     {
-        private static readonly Database _data;
+        private IDatabase _data { get; }
 
-        static MainPageViewModel()
-        {
-            _data = new Database();
-        }
-
-        private INavigationService _nav;
+        private INavigationService _navigationService { get; }
 
-        public MainPageViewModel()
+        public MainPageViewModel(IDatabase data, INavigationService navigationService)
         {
-            PropertyChanged += (s, e) =>
-            {
-                if (e.PropertyName.Equals(nameof(SearchString)))
-                {
-                    FillMembers();
-                }
-            };
+            _data = data;
+            _navigationService = navigationService;
+            ItemSelectedCommand = new DelegateCommand<Member>(OnItemSelectedCommandExecuted);
         }
 
         public async Task OnNavigatedToAsync(INavigationParameters parameters)
         {
-            _nav = parameters.GetNavigationService();
             await _data.OpenAsync();
             FillMembers();
         }
@@ -45,9 +38,11 @@ public async Task OnNavigatedToAsync(INavigationParameters parameters)
         public string SearchString
         {
             get => _searchString;
-            set => SetProperty(ref _searchString, value);
+            set => SetProperty(ref _searchString, value, onChanged: FillMembers);
         }
 
+        public DelegateCommand<Member> ItemSelectedCommand { get; }
+
         private void FillMembers()
         {
             Members.Clear();
@@ -71,12 +66,9 @@ IEnumerable<Member> GetFilteredMembers(Show show)
             }
         }
 
-        public async void ItemClick(object sender, Windows.UI.Xaml.Controls.ItemClickEventArgs e)
+        private async void OnItemSelectedCommandExecuted(Member member)
         {
-            if (e.ClickedItem is Member m)
-            {
-                await _nav.NavigateAsync(nameof(Views.ItemPage), new DrillInNavigationTransitionInfo(), (nameof(Member), m.ToJson()));
-            }
+            await _navigationService.NavigateAsync("ItemPage", new DrillInNavigationTransitionInfo(), ("member", member));
         }
     }
 }

Sandbox/Windows10/HelloWorld/HelloWorld.Unity/Views/ItemPage.xaml

@@ -2,7 +2,6 @@
     x:Class="Sample.Views.ItemPage"
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-    xmlns:local="using:Sample.Views"
     xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
     mc:Ignorable="d"
@@ -12,29 +11,29 @@
         <CommandBar IsDynamicOverflowEnabled="False">
             <CommandBar.Content>
                 <StackPanel Orientation="Horizontal">
-                    <Button Style="{StaticResource TextBlockButtonStyle}" Height="48" Width="52" Click="{x:Bind ViewModel.GoBack}" AccessKey="b">
+                    <Button Style="{StaticResource TextBlockButtonStyle}" Height="48" Width="52" Command="{Binding GoBackCommand}" AccessKey="b">
                         <SymbolIcon Symbol="Back" />
                     </Button>
-                    <TextBlock Text="{x:Bind ViewModel.Member.Character}" Margin="8,0" VerticalAlignment="Center" Style="{StaticResource TitleTextBlockStyle}" />
+                    <TextBlock Text="{Binding Member.Character}" Margin="8,0" VerticalAlignment="Center" Style="{StaticResource TitleTextBlockStyle}" />
                 </StackPanel>
             </CommandBar.Content>
         </CommandBar>
     </Page.TopAppBar>
 
     <Grid Width="400" Height="400">
         <Grid.Background>
-            <ImageBrush ImageSource="{x:Bind ViewModel.Member.Image.Path}" Stretch="UniformToFill" />
+            <ImageBrush ImageSource="{Binding Member.Image.Path}" Stretch="UniformToFill" />
         </Grid.Background>
         <StackPanel VerticalAlignment="Bottom" Padding="16">
             <StackPanel.Background>
                 <SolidColorBrush Color="Black" Opacity=".5" />
             </StackPanel.Background>
-            <TextBlock Text="{x:Bind ViewModel.Member.Character}" Style="{StaticResource HeaderTextBlockStyle}" TextWrapping="NoWrap" TextTrimming="CharacterEllipsis" Foreground="White" />
+            <TextBlock Text="{Binding Member.Character}" Style="{StaticResource HeaderTextBlockStyle}" TextWrapping="NoWrap" TextTrimming="CharacterEllipsis" Foreground="White" />
             <TextBlock Style="{StaticResource CaptionTextBlockStyle}" TextWrapping="NoWrap" TextTrimming="CharacterEllipsis" Foreground="White">
-                <Run Text="{x:Bind ViewModel.Member.Species}" />
-                <Run Text="{x:Bind ViewModel.Member.Gender}" />
+                <Run Text="{Binding Member.Species}" />
+                <Run Text="{Binding Member.Gender}" />
             </TextBlock>
-            <TextBlock Text="{x:Bind ViewModel.Member.Actor}" Style="{StaticResource SubheaderTextBlockStyle}" TextWrapping="NoWrap" TextTrimming="CharacterEllipsis" Foreground="White" />
+            <TextBlock Text="{Binding Member.Actor}" Style="{StaticResource SubheaderTextBlockStyle}" TextWrapping="NoWrap" TextTrimming="CharacterEllipsis" Foreground="White" />
         </StackPanel>
     </Grid>
 

Sandbox/Windows10/HelloWorld/HelloWorld.Unity/Views/ItemPage.xaml.cs

@@ -8,7 +8,5 @@ public ItemPage()
         {
             InitializeComponent();
         }
-
-        ViewModels.ItemPageViewModel ViewModel => DataContext as ViewModels.ItemPageViewModel;
     }
 }

Sandbox/Windows10/HelloWorld/HelloWorld.Unity/Views/MainPage.xaml

@@ -2,34 +2,47 @@
     x:Class="Sample.Views.MainPage"
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-    xmlns:local="using:Sample.Views"
     xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    xmlns:i="using:Microsoft.Xaml.Interactivity"
+    xmlns:core="using:Microsoft.Xaml.Interactions.Core"
     xmlns:models="using:SampleData.StarTrek"
-    xmlns:viewmodels="using:Sample.ViewModels"
+    xmlns:converter="using:HelloWorld.Converters"
     xmlns:controls="using:Sample.Controls"
     mc:Ignorable="d"
     Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
 
     <Page.Resources>
-        <CollectionViewSource x:Name="cvs" IsSourceGrouped="True" Source="{x:Bind ViewModel.Members}" ItemsPath="Members" />
+        <CollectionViewSource x:Name="cvs" IsSourceGrouped="True" Source="{Binding Members}" ItemsPath="Members" />
+        <converter:ItemClickedConverter x:Name="itemClickedConverter" />
     </Page.Resources>
 
 <Page.TopAppBar>
     <CommandBar IsDynamicOverflowEnabled="False">
         <CommandBar.Content>
-            <TextBlock Text="Star Trek" VerticalAlignment="Center" Margin="16,8,0,0" 
-                        Style="{StaticResource TitleTextBlockStyle}" />
+            <TextBlock Text="Star Trek"
+                       VerticalAlignment="Center"
+                       Margin="16,8,0,0" 
+                       Style="{StaticResource TitleTextBlockStyle}" />
         </CommandBar.Content>
         <controls:AppBarLiteral>
-            <AutoSuggestBox QueryIcon="Find" PlaceholderText="Search" Width="250" Margin="0,8,4,0"
-                            Text="{x:Bind ViewModel.SearchString, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
+            <AutoSuggestBox QueryIcon="Find"
+                            PlaceholderText="Search"
+                            Width="250"
+                            Margin="0,8,4,0"
+                            Text="{Binding SearchString, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
         </controls:AppBarLiteral>
         <AppBarButton Label="Info" Icon="World" AccessKey="i" />
     </CommandBar>
 </Page.TopAppBar>
 
-    <GridView ItemsSource="{Binding Source={StaticResource cvs}}" IsItemClickEnabled="True" ItemClick="{x:Bind ViewModel.ItemClick}">
+    <GridView ItemsSource="{Binding Source={StaticResource cvs}}" IsItemClickEnabled="True">
+        <i:Interaction.Behaviors>
+            <core:EventTriggerBehavior EventName="ItemClick">
+                <core:InvokeCommandAction Command="{Binding ItemSelectedCommand}"
+                                          InputConverter="{StaticResource itemClickedConverter}" />
+            </core:EventTriggerBehavior>
+        </i:Interaction.Behaviors>
         <GridView.GroupStyle>
             <GroupStyle>
                 <GroupStyle.HeaderContainerStyle>

Sandbox/Windows10/HelloWorld/HelloWorld.Unity/Views/MainPage.xaml.cs

@@ -8,7 +8,5 @@ public MainPage()
         {
             InitializeComponent();
         }
-
-        ViewModels.MainPageViewModel ViewModel => DataContext as ViewModels.MainPageViewModel;
     }
 }

Sandbox/Windows10/SampleData/IDatabase.cs

@@ -0,0 +1,16 @@
+using System.Threading.Tasks;
+
+namespace SampleData.StarTrek
+{
+    public interface IDatabase
+    {
+        string[] Genders { get; }
+        Member[] Members { get; }
+        bool Open { get; }
+        Ship[] Ships { get; }
+        Show[] Shows { get; }
+        string[] Species { get; }
+
+        Task<bool> OpenAsync();
+    }
+}

Sandbox/Windows10/SampleData/SampleData.csproj

@@ -110,6 +110,7 @@
     <Compile Include="Email\Database.cs" />
     <Compile Include="Email\Message.cs" />
     <Compile Include="Email\Recipient.cs" />
+    <Compile Include="IDatabase.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="StarTrek\Database.cs" />
     <Compile Include="StarTrek\Image.cs" />

Sandbox/Windows10/SampleData/StarTrek/Database.cs

@@ -9,7 +9,7 @@
 
 namespace SampleData.StarTrek
 {
-    public class Database
+    public class Database : IDatabase
     {
         public Member[] Members { get; private set; }
 

Source/Windows10/Prism.Windows/Navigation/INavigationParametersExtensions.cs

@@ -41,16 +41,6 @@ public static NavigationMode GetNavigationMode(this INavigationParameters parame
             return (parameters as INavigationParametersInternal).GetValue<NavigationMode>(nameof(NavigationMode));
         }
 
-        public static INavigationService GetNavigationService(this INavigationParameters parameters)
-        {
-            if (!(parameters as INavigationParametersInternal).ContainsKey(nameof(NavigationService)))
-            {
-                return null;
-            }
-
-            return (parameters as INavigationParametersInternal).GetValue<INavigationService>(nameof(NavigationService));
-        }
-
         public static SynchronizationContext GetSynchronizationContext(this INavigationParameters parameters)
         {
             if (!(parameters as INavigationParametersInternal).ContainsKey(nameof(SynchronizationContext)))