Migrated to GetInteger() where appropriate

There's no need to parse integer values for e.g. `TopicId` or `ParentId`; this can now be done using `GetInteger()`. This has the added benefit of allowing more concrete validation of e.g. `ParentId` to ensure it is actually an integer (instead of simply not null).

Author: JeremyCaney

Ignia.Topics.Data.Sql/SqlTopicRepository.cs

@@ -190,7 +190,7 @@ private static void SetBlobAttributes(SqlDataReader reader, Dictionary<int, Topi
     ///   Adds relationships retrieved from an individual relationship record to their associated topics.
     /// </summary>
     /// <remarks>
-    ///   Topics can be cross-referenced with each other via a many-to-many relationships.Once the topics are populated in
+    ///   Topics can be cross-referenced with each other via a many-to-many relationships. Once the topics are populated in
     ///   memory, loop through the data to create these associations.
     /// </remarks>
     /// <param name="reader">The <see cref="System.Data.SqlClient.SqlDataReader"/> that representing the current record.</param>
@@ -213,7 +213,7 @@ private static void SetRelationships(SqlDataReader reader, Dictionary<int, Topic
       | Identify affected topics
       \-----------------------------------------------------------------------------------------------------------------------*/
       var current               = topics[sourceTopicId];
-      Topic related             = null;
+      var related               = (Topic)null;
 
       // Fetch the related topic
       if (topics.Keys.Contains(targetTopicId)) {
@@ -253,8 +253,8 @@ private static void SetDerivedTopics(Dictionary<int, Topic> topics) {
       | Loop through topics
       \-----------------------------------------------------------------------------------------------------------------------*/
       foreach (var topic in topics.Values) {
-        var success = Int32.TryParse(topic.Attributes.GetValue("TopicId", "-1", false, false), out var derivedTopicId);
-        if (!success || derivedTopicId < 0) continue;
+        var derivedTopicId = topic.Attributes.GetInteger("TopicId", -1, false, false);
+        if (derivedTopicId < 0) continue;
         if (topics.Keys.Contains(derivedTopicId)) {
           topic.DerivedTopic = topics[derivedTopicId];
         }
@@ -861,7 +861,7 @@ public override int Save(Topic topic, bool isRecursive = false, bool isDraft = f
       \-----------------------------------------------------------------------------------------------------------------------*/
       if (isRecursive) {
         foreach (var childTopic in topic.Children) {
-          Contract.Assume(childTopic.Attributes.GetValue("ParentID") != null, "Assumes the Parent ID AttributeValue is available.");
+          Contract.Assume(childTopic.Attributes.GetInteger("ParentID", -1) > 0, "Assumes the Parent ID AttributeValue is available.");
           childTopic.Attributes.SetValue("ParentID", returnVal.ToString());
           Save(childTopic, isRecursive, isDraft);
         }