Merge branch 'feature/TopicViewModel-records' into develop

The new C# 9.0 record feature is optimal for view models and binding models, which we don't expect to change after they've been generated. Records are also potentially a bit faster, since they're immutable. Finally, in the rare case that we _do_ need to make modifications, the `record` syntax makes it easy to generate new versions via shallow copies via the `with` syntax.

The nature of records mandates that all downstream implementations of view and binding models are also converted to records, so this is (very much!) a breaking change. Since view models _should_ be read-only, however, and will generally be mapped using e.g. the `ITopicMappingService`, we don't expect this to be a difficult migration for adopters.

Author: JeremyCaney

OnTopic.Tests/BindingModels/BasicTopicBindingModel.cs

@@ -26,10 +26,10 @@ public BasicTopicBindingModel(string? key, string? contentType) {
       ContentType = contentType;
     }
 
-    public string? Key { get; set; }
+    public string? Key { get; init; }
 
     [Required]
-    public string? ContentType { get; set; }
+    public string? ContentType { get; init; }
 
   } //Class
 } //Namespace

OnTopic.Tests/ReverseTopicMappingServiceTest.cs

@@ -369,7 +369,7 @@ public async Task Map_ExceedsMinimumValue_ThrowsValidationException() {
     ///   cref="InvalidOperationException"/>.
     /// </summary>
     [TestMethod]
-    [ExpectedException(typeof(TopicMappingException))]
+    [ExpectedException(typeof(MappingModelValidationException))]
     public async Task Map_InvalidChildrenProperty_ThrowsInvalidOperationException() {
 
       var mappingService        = new ReverseTopicMappingService(_topicRepository);
@@ -387,7 +387,7 @@ public async Task Map_InvalidChildrenProperty_ThrowsInvalidOperationException()
     ///   cref="InvalidOperationException"/>.
     /// </summary>
     [TestMethod]
-    [ExpectedException(typeof(TopicMappingException))]
+    [ExpectedException(typeof(MappingModelValidationException))]
     public async Task Map_InvalidParentProperty_ThrowsInvalidOperationException() {
 
       var mappingService        = new ReverseTopicMappingService(_topicRepository);
@@ -408,7 +408,7 @@ public async Task Map_InvalidParentProperty_ThrowsInvalidOperationException() {
     ///   <see cref="InvalidOperationException"/>.
     /// </summary>
     [TestMethod]
-    [ExpectedException(typeof(TopicMappingException))]
+    [ExpectedException(typeof(MappingModelValidationException))]
     public async Task Map_InvalidAttribute_ThrowsInvalidOperationException() {
 
       var mappingService        = new ReverseTopicMappingService(_topicRepository);
@@ -426,7 +426,7 @@ public async Task Map_InvalidAttribute_ThrowsInvalidOperationException() {
     ///   is invalid, and expected to throw an <see cref="InvalidOperationException"/>.
     /// </summary>
     [TestMethod]
-    [ExpectedException(typeof(TopicMappingException))]
+    [ExpectedException(typeof(MappingModelValidationException))]
     public async Task Map_InvalidRelationshipBaseType_ThrowsInvalidOperationException() {
 
       var mappingService        = new ReverseTopicMappingService(_topicRepository);
@@ -446,7 +446,7 @@ public async Task Map_InvalidRelationshipBaseType_ThrowsInvalidOperationExceptio
     ///   cref="InvalidOperationException"/>.
     /// </summary>
     [TestMethod]
-    [ExpectedException(typeof(TopicMappingException))]
+    [ExpectedException(typeof(MappingModelValidationException))]
     public async Task Map_InvalidRelationshipType_ThrowsInvalidOperationException() {
 
       var mappingService        = new ReverseTopicMappingService(_topicRepository);
@@ -465,7 +465,7 @@ public async Task Map_InvalidRelationshipType_ThrowsInvalidOperationException()
     ///   cref="IList"/>. This is invalid, and expected to throw an <see cref="InvalidOperationException"/>.
     /// </summary>
     [TestMethod]
-    [ExpectedException(typeof(TopicMappingException))]
+    [ExpectedException(typeof(MappingModelValidationException))]
     public async Task Map_InvalidRelationshipListType_ThrowsInvalidOperationException() {
 
       var mappingService        = new ReverseTopicMappingService(_topicRepository);
@@ -484,7 +484,7 @@ public async Task Map_InvalidRelationshipListType_ThrowsInvalidOperationExceptio
     ///   cref="IRelatedTopicBindingModel"/>. This is invalid, and expected to throw an <see cref="InvalidOperationException"/>.
     /// </summary>
     [TestMethod]
-    [ExpectedException(typeof(TopicMappingException))]
+    [ExpectedException(typeof(MappingModelValidationException))]
     public async Task Map_InvalidTopicReferenceType_ThrowsInvalidOperationException() {
 
       var mappingService        = new ReverseTopicMappingService(_topicRepository);

OnTopic.Tests/ViewModels/DescendentSpecializedTopicViewModel.cs

@@ -24,7 +24,7 @@ namespace OnTopic.Tests.ViewModels {
   ///     This is a sample class intended for test purposes only; it is not designed for use in a production environment.
   ///   </para>
   /// </remarks>
-  public class DescendentSpecializedTopicViewModel: DescendentTopicViewModel {
+  public record DescendentSpecializedTopicViewModel: DescendentTopicViewModel {
 
     public bool IsLeaf { get; set; }
 

OnTopic.Tests/ViewModels/DescendentTopicViewModel.cs

@@ -23,7 +23,7 @@ namespace OnTopic.Tests.ViewModels {
   ///     This is a sample class intended for test purposes only; it is not designed for use in a production environment.
   ///   </para>
   /// </remarks>
-  public class DescendentTopicViewModel: TopicViewModel {
+  public record DescendentTopicViewModel: TopicViewModel {
 
     [Follow(Relationships.Children)]
     public TopicViewModelCollection<DescendentTopicViewModel> Children { get; } = new();

OnTopic.ViewModels/BindingModels/RelatedTopicBindingModel.cs

@@ -21,7 +21,7 @@ namespace OnTopic.ViewModels.BindingModels {
   ///   cref="ReverseTopicMappingService"/>. The only reason to implement a custom definition is if the caller needs additional
   ///   metadata for separate validation or processing.
   /// </remarks>
-  public class RelatedTopicBindingModel : IRelatedTopicBindingModel {
+  public record RelatedTopicBindingModel : IRelatedTopicBindingModel {
 
     /*==========================================================================================================================
     | PROPERTY: UNIQUE KEY
@@ -33,7 +33,7 @@ public class RelatedTopicBindingModel : IRelatedTopicBindingModel {
     ///   value is not null
     /// </requires>
     [Required]
-    public string? UniqueKey { get; set; }
+    public string? UniqueKey { get; init; }
 
   } //Class
 } //Namespaces

OnTopic.ViewModels/ContentItemTopicViewModel.cs

@@ -18,39 +18,39 @@ namespace OnTopic.ViewModels {
   ///   default implementations that can be used directly, used as base classes, or overwritten at the presentation level. They
   ///   are supplied for convenience to model factory default settings for out-of-the-box content types.
   /// </remarks>
-  public class ContentItemTopicViewModel: ItemTopicViewModel {
+  public record ContentItemTopicViewModel: ItemTopicViewModel {
 
     /*==========================================================================================================================
     | DESCRIPTION
     \-------------------------------------------------------------------------------------------------------------------------*/
     /// <summary>
     ///   Gets the description; for Content Items, this is effectively the body.
     /// </summary>
-    public string Description { get; set; } = default!;
+    public string Description { get; init; } = default!;
 
     /*==========================================================================================================================
     | LEARN MORE URL
     \-------------------------------------------------------------------------------------------------------------------------*/
     /// <summary>
     ///   Gets an optional URL for additional information that should be linked to.
     /// </summary>
-    public Uri? LearnMoreUrl { get; set; }
+    public Uri? LearnMoreUrl { get; init; }
 
     /*==========================================================================================================================
     | THUMBNAIL IMAGE
     \-------------------------------------------------------------------------------------------------------------------------*/
     /// <summary>
     ///   Gets an optional path to a thumbnail image that should accompany the content item.
     /// </summary>
-    public Uri? ThumbnailImage { get; set; }
+    public Uri? ThumbnailImage { get; init; }
 
     /*==========================================================================================================================
     | CATEGORY
     \-------------------------------------------------------------------------------------------------------------------------*/
     /// <summary>
     ///   Gets the category that the content item should be grouped under.
     /// </summary>
-    public string? Category { get; set; }
+    public string? Category { get; init; }
 
   } //Class
 } //Namespace

OnTopic.ViewModels/ContentListTopicViewModel.cs

@@ -17,7 +17,7 @@ namespace OnTopic.ViewModels {
   ///   default implementations that can be used directly, used as base classes, or overwritten at the presentation level. They
   ///   are supplied for convenience to model factory default settings for out-of-the-box content types.
   /// </remarks>
-  public class ContentListTopicViewModel: PageTopicViewModel {
+  public record ContentListTopicViewModel: PageTopicViewModel {
 
     /*==========================================================================================================================
     | CONTENT ITEMS
@@ -51,7 +51,7 @@ public class ContentListTopicViewModel: PageTopicViewModel {
     ///   corresponding attribute, and so this can easily be hidden or disabled globally via the editor.
     /// </remarks>
     /// <returns>True if the content list should be indexed; false otherwise.</returns>
-    public bool IsIndexed { get; set; }
+    public bool IsIndexed { get; init; }
 
     /*==========================================================================================================================
     | INDEX LABEL
@@ -64,8 +64,8 @@ public class ContentListTopicViewModel: PageTopicViewModel {
     ///   "IndexLabel"/> allows that to be optionally set on a per topic basis. The default value is "Contents", though it is up
     ///   to view implementors and editor configurations as to whether this option is exposed or honored.
     /// </remarks>
-    /// <returns>Returns the value set; defaults to "Contents".</returns>
-    public string IndexLabel { get; set; } = "Contents";
+    /// <returns>Returns the value init; defaults to "Contents".</returns>
+    public string IndexLabel { get; init; } = "Contents";
 
   } //Class
 } //Namespace

OnTopic.ViewModels/IndexTopicViewModel.cs

@@ -17,7 +17,7 @@ namespace OnTopic.ViewModels {
   ///   default implementations that can be used directly, used as base classes, or overwritten at the presentation level. They
   ///   are supplied for convenience to model factory default settings for out-of-the-box content types.
   /// </remarks>
-  public class IndexTopicViewModel: PageTopicViewModel {
+  public record IndexTopicViewModel: PageTopicViewModel {
 
 
   } //Class

OnTopic.ViewModels/Internal/IsExternalInit.cs

@@ -0,0 +1,19 @@
+/*==============================================================================================================================
+| Author        Ignia, LLC
+| Client        Ignia, LLC
+| Project       Topics Library
+\=============================================================================================================================*/
+
+namespace System.Runtime.CompilerServices {
+
+  /*============================================================================================================================
+  | CLASS: IS EXTERNAL INIT
+  \---------------------------------------------------------------------------------------------------------------------------*/
+  /// <summary>
+  ///   The <see cref="IsExternalInit"/> class is made available as part of the .NET 5.0 CLR in order to enable init accessors.
+  ///   As this is not available in .NET Standard, however, we must maintain this separate copy until we migrate to .NET 5.0.
+  /// </summary>
+  internal static class IsExternalInit {
+
+  } //Class
+} //Namespace

OnTopic.ViewModels/ItemTopicViewModel.cs

@@ -17,7 +17,7 @@ namespace OnTopic.ViewModels {
   ///   default implementations that can be used directly, used as base classes, or overwritten at the presentation level. They
   ///   are supplied for convenience to model factory default settings for out-of-the-box content types.
   /// </remarks>
-  public class ItemTopicViewModel : TopicViewModel {
+  public record ItemTopicViewModel : TopicViewModel {
 
 
   } //Class

OnTopic.ViewModels/ListTopicViewModel.cs

@@ -25,7 +25,7 @@ namespace OnTopic.ViewModels {
   ///     are supplied for convenience to model factory default settings for out-of-the-box content types.
   ///   </para>
   /// </remarks>
-  public class ListTopicViewModel: ContentItemTopicViewModel {
+  public record ListTopicViewModel: ContentItemTopicViewModel {
 
   } //Class
 } //Namespace

OnTopic.ViewModels/LookupListItemTopicViewModel.cs

@@ -17,7 +17,7 @@ namespace OnTopic.ViewModels {
   ///   default implementations that can be used directly, used as base classes, or overwritten at the presentation level. They
   ///   are supplied for convenience to model factory default settings for out-of-the-box content types.
   /// </remarks>
-  public class LookupListItemTopicViewModel: ItemTopicViewModel {
+  public record LookupListItemTopicViewModel: ItemTopicViewModel {
 
 
   } //Class

OnTopic.ViewModels/NavigationTopicViewModel.cs

@@ -28,15 +28,15 @@ namespace OnTopic.ViewModels {
   ///     cref="NavigationTopicViewModel"/> class is marked as <c>sealed</c>.
   ///   </para>
   /// </remarks>
-  public sealed class NavigationTopicViewModel : TopicViewModel, INavigationTopicViewModel<NavigationTopicViewModel> {
+  public sealed record NavigationTopicViewModel : TopicViewModel, INavigationTopicViewModel<NavigationTopicViewModel> {
 
     /*==========================================================================================================================
     | SHORT TITLE
     \-------------------------------------------------------------------------------------------------------------------------*/
     /// <summary>
     ///   Provides a short title to be used in the navigation, for cases where the normal title is too long.
     /// </summary>
-    public string? ShortTitle { get; set; }
+    public string? ShortTitle { get; init; }
 
     /*==========================================================================================================================
     | CHILDREN

OnTopic.ViewModels/PageGroupTopicViewModel.cs

@@ -17,7 +17,7 @@ namespace OnTopic.ViewModels {
   ///   default implementations that can be used directly, used as base classes, or overwritten at the presentation level. They
   ///   are supplied for convenience to model factory default settings for out-of-the-box content types.
   /// </remarks>
-  public class PageGroupTopicViewModel : SectionTopicViewModel {
+  public record PageGroupTopicViewModel : SectionTopicViewModel {
 
 
   } //Class

OnTopic.ViewModels/PageTopicViewModel.cs

@@ -18,59 +18,59 @@ namespace OnTopic.ViewModels {
   ///   default implementations that can be used directly, used as base classes, or overwritten at the presentation level. They
   ///   are supplied for convenience to model factory default settings for out-of-the-box content types.
   /// </remarks>
-  public class PageTopicViewModel: TopicViewModel, IPageTopicViewModel {
+  public record PageTopicViewModel: TopicViewModel, IPageTopicViewModel {
 
     /*==========================================================================================================================
     | SUBTITLE
     \-------------------------------------------------------------------------------------------------------------------------*/
     /// <summary>
     ///   Provides an optional subtitle which will typically be displayed under the title.
     /// </summary>
-    public string? Subtitle { get; set; }
+    public string? Subtitle { get; init; }
 
     /*==========================================================================================================================
     | META TITLE
     \-------------------------------------------------------------------------------------------------------------------------*/
     /// <summary>
     ///   Provides an optional title to be used in page's metadata, if it differs from the <see cref="TopicViewModel.Title"/>.
     /// </summary>
-    public string? MetaTitle { get; set; }
+    public string? MetaTitle { get; init; }
 
     /*==========================================================================================================================
     | META DESCRIPTION
     \-------------------------------------------------------------------------------------------------------------------------*/
     /// <inheritdoc />
-    public string? MetaDescription { get; set; }
+    public string? MetaDescription { get; init; }
 
     /*==========================================================================================================================
     | META KEYWORDS
     \-------------------------------------------------------------------------------------------------------------------------*/
     /// <inheritdoc />
-    public string? MetaKeywords { get; set; }
+    public string? MetaKeywords { get; init; }
 
     /*==========================================================================================================================
     | META KEYWORDS
     \-------------------------------------------------------------------------------------------------------------------------*/
     /// <summary>
     ///   Determines whether or not search engines are expected to index the page.
     /// </summary>
-    public bool? NoIndex { get; set; }
+    public bool? NoIndex { get; init; }
 
     /*==========================================================================================================================
     | SHORT TITLE
     \-------------------------------------------------------------------------------------------------------------------------*/
     /// <summary>
     ///   Provides a short title to be used in the navigation, for cases where the normal title is too long.
     /// </summary>
-    public string? ShortTitle { get; set; }
+    public string? ShortTitle { get; init; }
 
     /*==========================================================================================================================
     | BODY
     \-------------------------------------------------------------------------------------------------------------------------*/
     /// <summary>
     ///   Provides the primary content for the page, which is typically in HTML format.
     /// </summary>
-    public string? Body { get; set; }
+    public string? Body { get; init; }
 
   } //Class
 } //Namespace

OnTopic.ViewModels/SectionTopicViewModel.cs

@@ -19,15 +19,15 @@ namespace OnTopic.ViewModels {
   ///   default implementations that can be used directly, used as base classes, or overwritten at the presentation level. They
   ///   are supplied for convenience to model factory default settings for out-of-the-box content types.
   /// </remarks>
-  public class SectionTopicViewModel : TopicViewModel {
+  public record SectionTopicViewModel : TopicViewModel {
 
     /*==========================================================================================================================
     | HEADER IMAGE
     \-------------------------------------------------------------------------------------------------------------------------*/
     /// <summary>
     ///   Provides a header image which may be displayed at the top of a section.
     /// </summary>
-    public Uri? HeaderImageUrl { get; set; }
+    public Uri? HeaderImageUrl { get; init; }
 
   } //Class
 } //Namespace

OnTopic.ViewModels/SlideTopicViewModel.cs

@@ -17,7 +17,7 @@ namespace OnTopic.ViewModels {
   ///   default implementations that can be used directly, used as base classes, or overwritten at the presentation level. They
   ///   are supplied for convenience to model factory default settings for out-of-the-box content types.
   /// </remarks>
-  public class SlideTopicViewModel: ContentItemTopicViewModel {
+  public record SlideTopicViewModel: ContentItemTopicViewModel {
 
 
   } //Class