[AOT compatible] Clean up some AOT build issue in FilePreviewCommon and MarkdownPreviewHandler (#36207)

* Use AppContext.BaseDirectory to replace assembly.GetExeAseembly.Location.
Fix json serilizer aot issue.

* clean up some AOT build issue

* Update src/modules/previewpane/MarkdownPreviewHandler/MarkdownPreviewHandlerControl.cs

Co-authored-by: Jeremy Sinclair <4016293+snickler@users.noreply.github.com>

* Update src/common/FilePreviewCommon/Formatters/JsonFormatter.cs

Co-authored-by: Jeremy Sinclair <4016293+snickler@users.noreply.github.com>

---------

Co-authored-by: Yu Leng (from Dev Box) <yuleng@microsoft.com>
Co-authored-by: Jeremy Sinclair <4016293+snickler@users.noreply.github.com>

src/common/FilePreviewCommon/FilePreviewCommon.csproj

@@ -2,6 +2,7 @@
   <!-- Look at Directory.Build.props in root for common stuff as well -->
   <Import Project="..\..\Common.Dotnet.CsWinRT.props" />
   <Import Project="..\..\Monaco.props" />
+  <Import Project="..\..\Common.Dotnet.AotCompatibility.props" />
 
   <PropertyGroup>
     <Description>PowerToys FilePreviewCommon</Description>

src/common/FilePreviewCommon/Formatters/FilePreviewJsonSerializerContext.cs

@@ -0,0 +1,14 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace Microsoft.PowerToys.FilePreviewCommon.Monaco.Formatters;
+
+[JsonSourceGenerationOptions(WriteIndented = true)]
+[JsonSerializable(typeof(JsonDocument))]
+internal sealed partial class FilePreviewJsonSerializerContext : JsonSerializerContext
+{
+}

src/common/FilePreviewCommon/Formatters/JsonFormatter.cs

@@ -14,7 +14,6 @@ namespace Microsoft.PowerToys.FilePreviewCommon.Monaco.Formatters
 
         private static readonly JsonSerializerOptions _serializerOptions = new JsonSerializerOptions
         {
-            WriteIndented = true,
             Encoder = JavaScriptEncoder.UnsafeRelaxedJsonEscaping,
         };
 
@@ -28,7 +27,8 @@ namespace Microsoft.PowerToys.FilePreviewCommon.Monaco.Formatters
 
             using (var jDocument = JsonDocument.Parse(value, new JsonDocumentOptions { CommentHandling = JsonCommentHandling.Skip }))
             {
-                return JsonSerializer.Serialize(jDocument, _serializerOptions);
+                FilePreviewJsonSerializerContext context = new(_serializerOptions);
+                return JsonSerializer.Serialize(jDocument, context.JsonDocument);
             }
         }
     }

src/common/FilePreviewCommon/MonacoHelper.cs

@@ -6,9 +6,7 @@ using System;
 using System.Collections.Generic;
 using System.Globalization;
 using System.IO;
-using System.Reflection;
 using System.Text.Json;
-
 using Microsoft.PowerToys.FilePreviewCommon.Monaco.Formatters;
 
 namespace Microsoft.PowerToys.FilePreviewCommon
@@ -38,15 +36,15 @@ namespace Microsoft.PowerToys.FilePreviewCommon
 
         private static string GetRuntimeMonacoDirectory()
         {
-            string exePath = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location) ?? string.Empty;
+            string baseDirectory = AppContext.BaseDirectory ?? string.Empty;
 
             // If the executable is within "WinUI3Apps", correct the path first.
-            if (Path.GetFileName(exePath) == "WinUI3Apps")
+            if (Path.GetFileName(baseDirectory) == "WinUI3Apps")
             {
-                exePath = Path.Combine(exePath, "..");
+                baseDirectory = Path.Combine(baseDirectory, "..");
             }
 
-            string monacoPath = Path.Combine(exePath, "Assets", "Monaco");
+            string monacoPath = Path.Combine(baseDirectory, "Assets", "Monaco");
 
             return Directory.Exists(monacoPath) ?
                 monacoPath :

src/modules/previewpane/MarkdownPreviewHandler/MarkdownPreviewHandler.csproj

@@ -1,7 +1,8 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
   <!-- Look at Directory.Build.props in root for common stuff as well -->
   <Import Project="..\..\..\Common.Dotnet.CsWinRT.props" />
   <Import Project="..\..\..\Common.SelfContained.props" />
+  <Import Project="..\..\..\Common.Dotnet.AotCompatibility.props" />
 
   <PropertyGroup>
     <ImplicitUsings>enable</ImplicitUsings>

src/modules/previewpane/MarkdownPreviewHandler/MarkdownPreviewHandlerControl.cs

@@ -20,7 +20,7 @@ namespace Microsoft.PowerToys.PreviewHandler.Markdown
     /// <summary>
     /// Win Form Implementation for Markdown Preview Handler.
     /// </summary>
-    public class MarkdownPreviewHandlerControl : FormHandlerControl
+    public partial class MarkdownPreviewHandlerControl : FormHandlerControl
     {
         private static readonly IFileSystem FileSystem = new FileSystem();
         private static readonly IPath Path = FileSystem.Path;
@@ -66,7 +66,7 @@ namespace Microsoft.PowerToys.PreviewHandler.Markdown
         {
             get
             {
-                string codeBase = Assembly.GetExecutingAssembly().Location;
+                string codeBase = AppContext.BaseDirectory;
                 UriBuilder uri = new UriBuilder(codeBase);
                 string path = Uri.UnescapeDataString(uri.Path);
                 return Path.GetDirectoryName(path);