SystemSerializer update for BaseObjectStorageHelper (#3702)

## Fixes #3692
This introduces a new light-weight serializer which we can use within the toolkit for the `SystemInformation` class still. And then developers with more complex type needs can specify their own serializer for the `BaseObjectStorageHelper` classes. See the related issue for more details.

Follow-on to #3637 and #3414

## PR Type
What kind of change does this PR introduce?
<!-- Please uncomment one or more that apply to this PR. -->

<!-- - Bugfix -->
- Feature
<!-- - Code style update (formatting) -->
- Refactoring (no functional changes, no api changes)
<!-- - Build or CI related changes -->
<!-- - Documentation content changes -->
<!-- - Sample app changes -->
<!-- - Other... Please describe: -->


## What is the current behavior?
Using `DataContractJsonSerializer`, though we had used `Newtonsoft.Json` in 6.1.

## What is the new behavior?
Use new `SystemSerializer` which passes values to/from the Windows `ApplicationDataContainer` APIs directly. Updates our internal usages of this to the new system. Requires developer using the `BaseObjectStorageHelper` to provide a serializer implementation.

This of course does provide a 'default'/system information within the toolkit now compared to our original thought of providing none at all before the `SystemInformation` problem was identified.

## PR Checklist

Please check if your PR fulfills the following requirements:

- [x] Tested code with current [supported SDKs](../readme.md#supported)
- [ ] Pull Request has been submitted to the documentation repository [instructions](..\contributing.md#docs). Link: <!-- docs PR link -->
- [ ] Sample in sample app has been added / updated (for bug fixes / features)
    - [ ] Icon has been created (if new sample) following the [Thumbnail Style Guide and templates](https://github.com/windows-toolkit/WindowsCommunityToolkit-design-assets)
- [ ] New major technical changes in the toolkit have or will be added to the [Wiki](https://github.com/windows-toolkit/WindowsCommunityToolkit/wiki) e.g. build changes, source generators, testing infrastructure, sample creation changes, etc...
- [ ] Tests for the changes have been added (for bug fixes / features) (if applicable)
- [ ] Header has been added to all new source files (run *build/UpdateHeaders.bat*)
- [ ] Contains **NO** breaking changes

<!-- If this PR contains a breaking change, please describe the impact and migration path for existing applications below. 
     Please note that breaking changes are likely to be rejected within minor release cycles or held until major versions. -->

## Other information
I tested copying the system.dat file from the Settings folder of our 6.1 sample app to the development version with the changes, no issues with `SystemInformation` reading the old data.

Updated/added unit tests to test the old json layer vs. reading from the new SystemSerializer as well as just testing a new `System.Text.Json` complex scenario. Added tests for exceptions.

TODO:
- [ ] Add more tests?
- [x] Run XAML Islands SystemInformation test
- [ ] Do we want `SystemSerializer` to handle a few more 'basic' (but non-primitive) types? E.g. @Sergio0694 has a [similar implementation for a different related system](https://github.com/Sergio0694/Brainf_ckSharp/blob/master/src/Brainf_ckSharp.Services.Uwp/SettingsService.cs)
- [ ] ???

Author: msftbot[bot]

GazeInputTest/GazeInputTest.csproj

@@ -12,7 +12,7 @@
     <DefaultLanguage>en-US</DefaultLanguage>
     <TargetPlatformIdentifier>UAP</TargetPlatformIdentifier>
     <TargetPlatformVersion Condition=" '$(TargetPlatformVersion)' == '' ">10.0.19041.0</TargetPlatformVersion>
-    <TargetPlatformMinVersion>10.0.17134.0</TargetPlatformMinVersion>
+    <TargetPlatformMinVersion>10.0.17763.0</TargetPlatformMinVersion>
     <MinimumVisualStudioVersion>14</MinimumVisualStudioVersion>
     <FileAlignment>512</FileAlignment>
     <ProjectTypeGuids>{A5A43C5B-DE2A-4C0C-9213-0A381AF9435A};{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}</ProjectTypeGuids>

Microsoft.Toolkit.Uwp.SampleApp/Controls/SampleAppMarkdownRenderer.cs

@@ -416,7 +416,7 @@ public string DesiredLang
         /// <summary>
         /// The Local Storage Helper.
         /// </summary>
-        private LocalObjectStorageHelper storage = new LocalObjectStorageHelper();
+        private LocalObjectStorageHelper storage = new LocalObjectStorageHelper(new SystemSerializer());
 
         /// <summary>
         /// DocFX note types and styling info, keyed by identifier.

Microsoft.Toolkit.Uwp.SampleApp/Models/Sample.cs

@@ -39,7 +39,7 @@ public class Sample
 
         public static async void EnsureCacheLatest()
         {
-            var settingsStorage = new LocalObjectStorageHelper();
+            var settingsStorage = new LocalObjectStorageHelper(new SystemSerializer());
 
             var onlineDocsSHA = await GetDocsSHA();
             var cacheSHA = settingsStorage.Read<string>(_cacheSHAKey);

Microsoft.Toolkit.Uwp.SampleApp/Models/Samples.cs

@@ -21,7 +21,7 @@ public static class Samples
         private static SemaphoreSlim _semaphore = new SemaphoreSlim(1);
 
         private static LinkedList<Sample> _recentSamples;
-        private static RoamingObjectStorageHelper _roamingObjectStorageHelper = new RoamingObjectStorageHelper();
+        private static LocalObjectStorageHelper _localObjectStorageHelper = new LocalObjectStorageHelper(new SystemSerializer());
 
         public static async Task<SampleCategory> GetCategoryBySample(Sample sample)
         {
@@ -98,7 +98,7 @@ public static async Task<LinkedList<Sample>> GetRecentSamples()
             if (_recentSamples == null)
             {
                 _recentSamples = new LinkedList<Sample>();
-                var savedSamples = _roamingObjectStorageHelper.Read<string>(_recentSamplesStorageKey);
+                var savedSamples = _localObjectStorageHelper.Read<string>(_recentSamplesStorageKey);
 
                 if (savedSamples != null)
                 {
@@ -144,7 +144,7 @@ private static void SaveRecentSamples()
             }
 
             var str = string.Join(";", _recentSamples.Take(10).Select(s => s.Name).ToArray());
-            _roamingObjectStorageHelper.Save<string>(_recentSamplesStorageKey, str);
+            _localObjectStorageHelper.Save<string>(_recentSamplesStorageKey, str);
         }
     }
 }

Microsoft.Toolkit.Uwp.SampleApp/SamplePages/Object Storage/ObjectStoragePage.xaml

@@ -1,26 +1,33 @@
-<Page
-    x:Class="Microsoft.Toolkit.Uwp.SampleApp.SamplePages.ObjectStoragePage"
-    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
-    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
-    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
-    mc:Ignorable="d">
+<Page x:Class="Microsoft.Toolkit.Uwp.SampleApp.SamplePages.ObjectStoragePage"
+      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+      xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+      xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+      mc:Ignorable="d">
 
     <ScrollViewer>
         <StackPanel Margin="20">
-            <ToggleSwitch x:Name="StorageModeToggle" HorizontalAlignment="Center" 
-                          OnContent="Roaming storage (save across all your devices)"
-                          OffContent="Local storage (save on this device only)" />
+            <TextBox x:Name="KeyTextBox"
+                     Margin="0,10,0,0"
+                     PlaceholderText="Key" />
 
-            <TextBox x:Name="KeyTextBox" PlaceholderText="Key" Margin="0 10 0 0" />
+            <TextBox x:Name="ContentTextBox"
+                     Margin="0,10,0,0"
+                     PlaceholderText="Content to save" />
 
-            <TextBox x:Name="ContentTextBox" PlaceholderText="Content to save" Margin="0 10 0 0" />
-
-            <StackPanel Margin="0 10 0 0" Orientation="Horizontal" HorizontalAlignment="Center">
-                <Button x:Name="ReadButton" Content="Read from key" HorizontalAlignment="Center" Margin="5 0"
-                        Click="ReadButton_Click" />
-                <Button x:Name="SaveButton" Content="Save" HorizontalAlignment="Center" Margin="5 0"
-                        Click="SaveButton_Click" />
+            <StackPanel Margin="0,10,0,0"
+                        HorizontalAlignment="Center"
+                        Orientation="Horizontal">
+                <Button x:Name="ReadButton"
+                        Margin="5,0"
+                        HorizontalAlignment="Center"
+                        Click="ReadButton_Click"
+                        Content="Read from key" />
+                <Button x:Name="SaveButton"
+                        Margin="5,0"
+                        HorizontalAlignment="Center"
+                        Click="SaveButton_Click"
+                        Content="Save" />
             </StackPanel>
         </StackPanel>
     </ScrollViewer>

Microsoft.Toolkit.Uwp.SampleApp/SamplePages/Object Storage/ObjectStoragePage.xaml.cs

@@ -9,8 +9,7 @@ namespace Microsoft.Toolkit.Uwp.SampleApp.SamplePages
 {
     public sealed partial class ObjectStoragePage
     {
-        private readonly IObjectStorageHelper localStorageHelper = new LocalObjectStorageHelper();
-        private readonly IObjectStorageHelper roamingStorageHelper = new RoamingObjectStorageHelper();
+        private readonly IObjectStorageHelper localStorageHelper = new LocalObjectStorageHelper(new SystemSerializer());
 
         public ObjectStoragePage()
         {
@@ -24,21 +23,10 @@ private void ReadButton_Click(object sender, RoutedEventArgs e)
                 return;
             }
 
-            if (StorageModeToggle.IsOn)
+            // Read from local storage
+            if (localStorageHelper.KeyExists(KeyTextBox.Text))
             {
-                // Read from roaming storage
-                if (roamingStorageHelper.KeyExists(KeyTextBox.Text))
-                {
-                    ContentTextBox.Text = roamingStorageHelper.Read<string>(KeyTextBox.Text);
-                }
-            }
-            else
-            {
-                // Read from local storage
-                if (localStorageHelper.KeyExists(KeyTextBox.Text))
-                {
-                    ContentTextBox.Text = localStorageHelper.Read<string>(KeyTextBox.Text);
-                }
+                ContentTextBox.Text = localStorageHelper.Read<string>(KeyTextBox.Text);
             }
         }
 
@@ -54,16 +42,8 @@ private void SaveButton_Click(object sender, RoutedEventArgs e)
                 return;
             }
 
-            if (StorageModeToggle.IsOn)
-            {
-                // Save into roaming storage
-                roamingStorageHelper.Save(KeyTextBox.Text, ContentTextBox.Text);
-            }
-            else
-            {
-                // Save into local storage
-                localStorageHelper.Save(KeyTextBox.Text, ContentTextBox.Text);
-            }
+            // Save into local storage
+            localStorageHelper.Save(KeyTextBox.Text, ContentTextBox.Text);
         }
     }
 }

Microsoft.Toolkit.Uwp/Helpers/ObjectStorage/BaseObjectStorageHelper.cs

@@ -21,14 +21,13 @@ public abstract class BaseObjectStorageHelper : IObjectStorageHelper
         /// <summary>
         /// Initializes a new instance of the <see cref="BaseObjectStorageHelper"/> class,
         /// which can read and write data using the provided <see cref="IObjectSerializer"/>;
-        /// if none is provided, a default Json serializer will be used (based on <see cref="DataContractSerializer"/>).
-        /// In 6.1 and older the default Serializer was based on Newtonsoft.Json and the new default Serializer may behave differently.
+        /// In 6.1 and older the default Serializer was based on Newtonsoft.Json.
         /// To implement a <see cref="IObjectSerializer"/> based on Newtonsoft.Json or System.Text.Json see https://aka.ms/wct/storagehelper-migration
         /// </summary>
         /// <param name="objectSerializer">The serializer to use.</param>
-        public BaseObjectStorageHelper(IObjectSerializer objectSerializer = null)
+        public BaseObjectStorageHelper(IObjectSerializer objectSerializer)
         {
-            serializer = objectSerializer ?? new JsonObjectSerializer();
+            serializer = objectSerializer ?? throw new ArgumentNullException(nameof(objectSerializer));
         }
 
         /// <summary>
@@ -85,15 +84,7 @@ public bool KeyExists(string compositeKey, string key)
                 return @default;
             }
 
-            var type = typeof(T);
-            var typeInfo = type.GetTypeInfo();
-
-            if (typeInfo.IsPrimitive || type == typeof(string))
-            {
-                return (T)Convert.ChangeType(value, type);
-            }
-
-            return serializer.Deserialize<T>((string)value);
+            return serializer.Deserialize<T>(value);
         }
 
         /// <summary>
@@ -132,14 +123,7 @@ public void Save<T>(string key, T value)
             var type = typeof(T);
             var typeInfo = type.GetTypeInfo();
 
-            if (typeInfo.IsPrimitive || type == typeof(string))
-            {
-                Settings.Values[key] = value;
-            }
-            else
-            {
-                Settings.Values[key] = serializer.Serialize(value);
-            }
+            Settings.Values[key] = serializer.Serialize(value);
         }
 
         /// <summary>
@@ -214,7 +198,7 @@ public Task<bool> FileExistsAsync(string filePath)
         /// <returns>The <see cref="StorageFile"/> where the object was saved</returns>
         public Task<StorageFile> SaveFileAsync<T>(string filePath, T value)
         {
-            return StorageFileHelper.WriteTextToFileAsync(Folder, serializer.Serialize(value), filePath, CreationCollisionOption.ReplaceExisting);
+            return StorageFileHelper.WriteTextToFileAsync(Folder, serializer.Serialize(value)?.ToString(), filePath, CreationCollisionOption.ReplaceExisting);
         }
     }
 }

Microsoft.Toolkit.Uwp/Helpers/ObjectStorage/IObjectSerializer.cs

@@ -10,19 +10,19 @@ namespace Microsoft.Toolkit.Uwp.Helpers
     public interface IObjectSerializer
     {
         /// <summary>
-        /// Serialize an object into a string.
+        /// Serialize an object into a string. It is recommended to use strings as the final format for objects if you plan to use the <see cref="BaseObjectStorageHelper.SaveFileAsync{T}(string, T)"/> method.
         /// </summary>
         /// <typeparam name="T">The type of the object to serialize.</typeparam>
         /// <param name="value">The object to serialize.</param>
         /// <returns>The serialized object.</returns>
-        string Serialize<T>(T value);
+        object Serialize<T>(T value);
 
         /// <summary>
-        /// Deserialize a string into an object.
+        /// Deserialize a primitive or string into an object of the given type.
         /// </summary>
         /// <typeparam name="T">The type of the deserialized object.</typeparam>
         /// <param name="value">The string to deserialize.</param>
         /// <returns>The deserialized object.</returns>
-        T Deserialize<T>(string value);
+        T Deserialize<T>(object value);
     }
 }

Microsoft.Toolkit.Uwp/Helpers/ObjectStorage/JsonObjectSerializer.cs

@@ -15,12 +15,11 @@ public class LocalObjectStorageHelper : BaseObjectStorageHelper
         /// <summary>
         /// Initializes a new instance of the <see cref="LocalObjectStorageHelper"/> class,
         /// which can read and write data using the provided <see cref="IObjectSerializer"/>;
-        /// if none is provided, a default Json serializer will be used (based on <see cref="DataContractSerializer"/>).
-        /// In 6.1 and older the default Serializer was based on Newtonsoft.Json and the new default Serializer may behave differently.
-        /// To implement a <see cref="IObjectSerializer"/> based on Newtonsoft.Json or System.Text.Json see https://aka.ms/wct/storagehelper-migration
+        /// In 6.1 and older the default Serializer was based on Newtonsoft.Json.
+        /// To implement an <see cref="IObjectSerializer"/> based on System.Text.Json, Newtonsoft.Json, or DataContractJsonSerializer see https://aka.ms/wct/storagehelper-migration
         /// </summary>
         /// <param name="objectSerializer">The serializer to use.</param>
-        public LocalObjectStorageHelper(IObjectSerializer objectSerializer = null)
+        public LocalObjectStorageHelper(IObjectSerializer objectSerializer)
             : base(objectSerializer)
         {
             Settings = ApplicationData.Current.LocalSettings;