Workaround for a XAML codegen issue

{x:Bind OneWay} still creates the code to set the bound properties in XamlTypeInfo.g.cs even though that's never actually used. If that property is init-only, that fails to build. Ideally these bindings should just omit those methods entirely.

Author: Sergio0694

samples/MvvmSample.Core/Models/Post.cs

@@ -17,7 +17,7 @@ public sealed class PostsQueryResponse
         /// Gets or sets the listing data for the response.
         /// </summary>
         [JsonPropertyName("data")]
-        public PostListing? Data { get; init; }
+        public PostListing? Data { get; set; }
     }
 
     /// <summary>
@@ -29,7 +29,7 @@ public sealed class PostListing
         /// Gets or sets the items in this listing.
         /// </summary>
         [JsonPropertyName("children")]
-        public IList<PostData>? Items { get; init; }
+        public IList<PostData>? Items { get; set; }
     }
 
     /// <summary>
@@ -41,7 +41,7 @@ public sealed class PostData
         /// Gets or sets the <see cref="Post"/> instance.
         /// </summary>
         [JsonPropertyName("data")]
-        public Post? Data { get; init; }
+        public Post? Data { get; set; }
     }
 
     /// <summary>
@@ -53,13 +53,13 @@ public sealed class Post
         /// Gets or sets the title of the post.
         /// </summary>
         [JsonPropertyName("title")]
-        public string? Title { get; init; }
+        public string? Title { get; set; }
 
         /// <summary>
         /// Gets or sets the URL to the post thumbnail, if present.
         /// </summary>
         [JsonPropertyName("thumbnail")]
-        public string? Thumbnail { get; init; }
+        public string? Thumbnail { get; set; }
 
         /// <summary>
         /// Gets the text of the post.

samples/MvvmSample.Core/Models/System.Runtime.CompilerServices/IsExternalInit.cs

@@ -18,7 +18,7 @@
     <ProjectTypeGuids>{A5A43C5B-DE2A-4C0C-9213-0A381AF9435A};{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}</ProjectTypeGuids>
     <WindowsXamlEnableOverview>true</WindowsXamlEnableOverview>
     <AppxPackageSigningEnabled>false</AppxPackageSigningEnabled>
-    <LangVersion>8.0</LangVersion>
+    <LangVersion>9.0</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Debug|x86'">
     <DebugSymbols>true</DebugSymbols>