Marked DefaultConfiguration members as [Obsolete]

The `DefaultConfiguration` (and related `Configuration` and `GetConfigurationValue()` members) is a left-over of the legacy `AttributeDescriptor` model where attribute type configuration values were configured as a delimited string in an attribute. This is still required for backward compatibility with the legacy **ASP.NET WebForms** editor. The new **ASP.NET Core** editor does not use this, instead relying on the new `AttributeTypeDescriptor` classes, which provide direct access to each configuration value via the standard `Attributes.GetValue()` approach.

Author: JeremyCaney

Ignia.Topics.Tests/TopicMappingServiceTest.cs

@@ -639,15 +639,13 @@ public async Task MapCompatibleProperties() {
       var mappingService        = new TopicMappingService(_topicRepository, new FakeViewModelLookupService());
       var topic                 = (AttributeDescriptor)TopicFactory.Create("Attribute", "AttributeDescriptor");
 
-      topic.DefaultConfiguration = "Value1=1&Value2=2";
       topic.EditorType          = "TopicList";
 
       topic.VersionHistory.Add(new DateTime(1976, 10, 15, 9, 30, 00));
 
       var target                = (CompatiblePropertyTopicViewModel?)await mappingService.MapAsync<CompatiblePropertyTopicViewModel>(topic).ConfigureAwait(false);
 
       Assert.AreEqual<ModelType>(topic.ModelType, target.ModelType);
-      Assert.AreEqual<IDictionary<string, string?>>(topic.Configuration, target.Configuration);
       Assert.AreEqual<int>(1, target.VersionHistory.Count);
 
     }

Ignia.Topics.Tests/TopicTest.cs

@@ -273,6 +273,8 @@ public void DerivedTopic() {
     [TestMethod]
     public void AttributeConfiguration() {
 
+      #pragma warning disable CS0618 // Type or member is obsolete
+
       var attribute = (AttributeDescriptor)TopicFactory.Create("Topic", "AttributeDescriptor");
       attribute.DefaultConfiguration = "IsRequired=\"True\" DisplayName=\"Display Name\"";
 
@@ -284,6 +286,8 @@ public void AttributeConfiguration() {
       Assert.ReferenceEquals("True", attribute.GetConfigurationValue("DisplayName"));
       Assert.ReferenceEquals("NotFound", attribute.GetConfigurationValue("MissingAttribute", "NotFound"));
 
+      #pragma warning restore CS0618 // Type or member is obsolete
+
     }
 
   } //Class

Ignia.Topics/Metadata/AttributeDescriptor.cs

@@ -215,6 +215,11 @@ public string? DisplayGroup {
     ///     User Controls as well as AngularJS Directives, the format is Property1="Value" Propert2="Value".
     ///   </para>
     /// </remarks>
+    [Obsolete(
+      "The DefaultConfiguration property is exclusively provided for backward compatibility with the legacy ASP.NET WebForms " +
+      "version of the OnTopic Editor. New implementations should use the new strongly typed AttributeTypeDescriptor model " +
+      "instead."
+    )]
     public string DefaultConfiguration {
       get => Attributes.GetValue("DefaultConfiguration", "")?? "";
       set {
@@ -230,6 +235,11 @@ public string DefaultConfiguration {
     ///   Retrieves a dictionary representing a parsed collection of key/value pairs from the
     ///   <see cref="DefaultConfiguration"/>.
     /// </summary>
+    [Obsolete(
+      "The Configuration property is exclusively provided for backward compatibility with the legacy ASP.NET WebForms " +
+      "version of the OnTopic Editor. New implementations should use the new strongly typed AttributeTypeDescriptor model " +
+      "instead."
+    )]
     public IDictionary<string, string?> Configuration {
       get {
         if (_configuration.Count.Equals(0) && DefaultConfiguration.Length > 0) {
@@ -252,6 +262,11 @@ public string DefaultConfiguration {
     ///   Retrieves a configuration value from the <see cref="Configuration"/> dictionary; if the value doesn't exist, then
     ///   optionally returns a default value.
     /// </summary>
+    [Obsolete(
+      "The GetConfigurationValue method is exclusively provided for backward compatibility with the legacy ASP.NET WebForms " +
+      "version of the OnTopic Editor. New implementations should use the new strongly typed AttributeTypeDescriptor model " +
+      "instead."
+    )]
     public string? GetConfigurationValue(string key, string? defaultValue = null) {
       Contract.Requires(!String.IsNullOrWhiteSpace(key));
       if (Configuration.ContainsKey(key) && Configuration[key] != null) {