chore: Adjusting native vs application

src/Uno.UWP/Storage/ApplicationData/ApplicationDataContainer.cs

@@ -16,7 +16,7 @@ namespace Windows.Storage;
 /// </remarks>
 public partial class ApplicationDataContainer : IDisposable
 {
-	private const string InternalSettingPrefix = "__";
+	internal const string InternalSettingPrefix = "__";
 	private const string ContainerSeparator = "¬";
 	private const string ContainerListKey = InternalSettingPrefix + "UnoContainers";
 
@@ -42,6 +42,8 @@ internal ApplicationDataContainer(ApplicationDataContainer parent, string name)
 
 	internal string ContainerPath => _parent is null ? "" : _parent.ContainerPath + InternalSettingPrefix + Name + ContainerSeparator;
 
+	internal string GetSettingKey(string key) => ContainerPath + key;
+
 	public ApplicationDataLocality Locality { get; }
 
 	public string Name { get; }

src/Uno.UWP/Storage/ApplicationData/ApplicationDataContainerSettings.cs

@@ -1,6 +1,8 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.Linq;
+using Uno.Extensions.Specialized;
 using Uno.Storage;
 using Windows.Foundation.Collections;
 
@@ -36,8 +38,8 @@ internal ApplicationDataContainerSettings(ApplicationDataContainer container, Ap
 	/// <returns></returns>
 	public object this[string key]
 	{
-		get => _nativeApplicationSettings[key];
-		set => _nativeApplicationSettings[key] = value;
+		get => _nativeApplicationSettings[_container.GetSettingKey(key)];
+		set => _nativeApplicationSettings[_container.GetSettingKey(key)] = value;
 	}
 
 	/// <summary>
@@ -49,19 +51,22 @@ public int Count
 	{
 		get
 		{
-			throw new global::System.NotSupportedException();
+			// Public settings count is equal to the total number of settings in the container excluding internal settings.
+			var allSettingsCount = _nativeApplicationSettings.GetKeysWithPrefix(_container.ContainerPath).Count();
+			var internalSettingsPath = _container.GetSettingKey(ApplicationDataContainer.InternalSettingPrefix);
+			var internalSettingsCount = _nativeApplicationSettings.GetKeysWithPrefix(internalSettingsPath).Count();
+
+			return allSettingsCount - internalSettingsCount;
 		}
 	}
 
 	public bool IsReadOnly => false;
 
-	public global::System.Collections.Generic.ICollection<string> Keys
-	{
-		get
-		{
-			throw new global::System.NotSupportedException();
-		}
-	}
+	public ICollection<string> Keys => _nativeApplicationSettings
+		.GetKeysWithPrefix(_container.ContainerPath)
+		.Except(
+			_nativeApplicationSettings.GetKeysWithPrefix(_container.GetSettingKey(ApplicationDataContainer.InternalSettingPrefix))
+		);
 
 	public global::System.Collections.Generic.ICollection<object> Values
 	{
@@ -139,4 +144,8 @@ internal void ClearIncludingInternal()
 	}
 
 	IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
+
+	private object DeserializeValue(string value) => DataTypeSerializer.Deserialize(value);
+
+	private string SerializeValue(object value) => DataTypeSerializer.Serialize(value);
 }

src/Uno.UWP/Storage/ApplicationData/Internal/INativeApplicationSettings.cs

@@ -9,6 +9,8 @@ namespace Uno.Storage;
 internal interface INativeApplicationSettings
 {
 	object this[string key] { get; set; }
-	ICollection<string> Keys { get; }
-	ICollection<object> Values { get; }
+
+	IEnumerable<string> Keys { get; }
+
+
 }

src/Uno.UWP/Storage/ApplicationData/Internal/NativeApplicationSettings.cs

@@ -3,7 +3,6 @@
 using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
-using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using Windows.Storage;
 
@@ -45,7 +44,7 @@ public object? this[string key]
 		{
 			if (TryGetSetting(key, out var value))
 			{
-				return DataTypeSerializer.Deserialize(value);
+				return DeserializeValue(value);
 			}
 
 			return null;
@@ -54,7 +53,7 @@ public object? this[string key]
 		{
 			if (value is not null)
 			{
-				SetSetting(key, DataTypeSerializer.Serialize(value));
+				SetSetting(key, SerializeValue(value));
 			}
 			else
 			{
@@ -67,8 +66,10 @@ public object? this[string key]
 
 	private partial bool TryGetSetting(string key, out string? value);
 
-	internal IEnumerable<string> GetKeysWithPrefix(string prefix)
-	{
-		return Keys.Where(kvp => kvp.StartsWith(prefix, StringComparison.InvariantCulture));
-	}
+	internal IEnumerable<string> GetKeysWithPrefix(string prefix) =>
+		Keys.Where(kvp => kvp.StartsWith(prefix, StringComparison.InvariantCulture));
+
+	private object? DeserializeValue(string? value) => DataTypeSerializer.Deserialize(value);
+
+	private string SerializeValue(object value) => DataTypeSerializer.Serialize(value);
 }

src/Uno.UWP/Storage/ApplicationData/Internal/NativeApplicationSettings.skia.cs

@@ -1,11 +1,11 @@
-using System;
+#nullable enable
+
+using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
-#nullable enable
-
 using Uno.Foundation.Logging;
 using Windows.Storage;
 
@@ -16,8 +16,8 @@ partial class NativeApplicationSettings
 	private static partial bool SupportsLocality() => true;
 
 	private readonly Dictionary<string, string> _values = new();
-	private string _folderPath;
-	private string _filePath;
+	private string _folderPath = null!;
+	private string _filePath = null!;
 
 	partial void InitializePlatform()
 	{
@@ -31,12 +31,6 @@ partial void InitializePlatform()
 
 	public ICollection<string> Keys => _values.Keys;
 
-	public ICollection<object> Values
-		=> _values.Values.Select(DataTypeSerializer.Deserialize).ToList();
-
-	public int Count
-		=> _values.Count;
-
 	public void Add(string key, object value)
 	{
 		if (ContainsKey(key))
@@ -94,7 +88,6 @@ private void ReadFromFile()
 	{
 		try
 		{
-
 			if (File.Exists(_filePath))
 			{
 				using (var reader = new BinaryReader(File.OpenRead(_filePath)))