Added custom event handler to create the relation for trashed nodes.

Removed the additional (AJAX) resource call from the Angular controller, as the relation removal is handled in server-side code during the move.

src/Umbraco.Core/Services/ContentService.cs

@@ -1131,9 +1131,6 @@ namespace Umbraco.Core.Services
                     return;
                 }
 
-                // Add a relation for the item being deleted, so that we can know the original parent for if we need to restore later
-                ApplicationContext.Current.Services.RelationService.Relate(content.Parent(), content, Constants.Conventions.Relations.RelateParentDocumentOnDelete);
-
                 var moveInfo = new List<MoveEventInfo<IContent>>
                 {
                     new MoveEventInfo<IContent>(content, originalPath, Constants.System.RecycleBinContent)

src/Umbraco.Web.UI.Client/src/views/content/content.restore.controller.js

@@ -7,13 +7,18 @@ angular.module("umbraco").controller("Umbraco.Editors.Content.RestoreController"
 		relationResource.getByChildId(node.id, "relateParentDocumentOnDelete").then(function (data) {
 			$scope.relation = data[0];
 
-			contentResource.getById($scope.relation.ParentId).then(function (data) {
-				$scope.target = data;
+			if ($scope.relation.ParentId == -1) {
+				$scope.target = { id: -1, name: "Root" };
 
-			}, function (err) {
-				$scope.success = false;
-				$scope.error = err;
-			});
+			} else {
+				contentResource.getById($scope.relation.ParentId).then(function (data) {
+					$scope.target = data;
+
+				}, function (err) {
+					$scope.success = false;
+					$scope.error = err;
+				});
+			}
 
 		}, function (err) {
 			$scope.success = false;
@@ -21,6 +26,7 @@ angular.module("umbraco").controller("Umbraco.Editors.Content.RestoreController"
 		});
 
 		$scope.restore = function () {
+			// this code was copied from `content.move.controller.js`
 			contentResource.move({ parentId: $scope.target.id, id: node.id })
 				.then(function (path) {
 					$scope.error = false;
@@ -43,9 +49,6 @@ angular.module("umbraco").controller("Umbraco.Editors.Content.RestoreController"
 						}
 					});
 
-					// remove the relation, as the item has been restored
-					relationResource.deleteById($scope.relation.Id);
-
 				}, function (err) {
 					$scope.success = false;
 					$scope.error = err;

src/Umbraco.Web/Strategies/RelateOnTrashHandler.cs

@@ -0,0 +1,65 @@
+using System;
+using System.Linq;
+using Umbraco.Core;
+using Umbraco.Core.Auditing;
+using Umbraco.Core.Events;
+using Umbraco.Core.Models;
+using Umbraco.Core.Services;
+
+namespace Umbraco.Web.Strategies
+{
+    public sealed class RelateOnTrashHandler : ApplicationEventHandler
+    {
+        protected override void ApplicationStarting(UmbracoApplicationBase umbracoApplication, ApplicationContext applicationContext)
+        {
+            ContentService.Moved += ContentService_Moved;
+            ContentService.Trashed += ContentService_Trashed;
+        }
+
+        private void ContentService_Moved(IContentService sender, MoveEventArgs<IContent> e)
+        {
+            foreach (var item in e.MoveInfoCollection.Where(x => x.OriginalPath.Contains(Constants.System.RecycleBinContent.ToInvariantString())))
+            {
+                var relationService = ApplicationContext.Current.Services.RelationService;
+                var relationTypeAlias = Constants.Conventions.RelationTypes.RelateParentDocumentOnDeleteAlias;
+                var relations = relationService.GetByChildId(item.Entity.Id);
+
+                foreach (var relation in relations.Where(x => x.RelationType.Alias.InvariantEquals(relationTypeAlias)))
+                {
+                    relationService.Delete(relation);
+                }
+            }
+        }
+
+        private void ContentService_Trashed(IContentService sender, MoveEventArgs<IContent> e)
+        {
+            var relationService = ApplicationContext.Current.Services.RelationService;
+            var relationTypeAlias = Constants.Conventions.RelationTypes.RelateParentDocumentOnDeleteAlias;
+            var relationType = relationService.GetRelationTypeByAlias(relationTypeAlias);
+
+            // check that the relation-type exists, if not, then recreate it
+            if (relationType == null)
+            {
+                var documentObjectType = new Guid(Constants.ObjectTypes.Document);
+                var relationTypeName = Constants.Conventions.RelationTypes.RelateParentDocumentOnDeleteName;
+
+                relationType = new RelationType(documentObjectType, documentObjectType, relationTypeAlias, relationTypeName);
+                relationService.Save(relationType);
+            }
+
+            foreach (var item in e.MoveInfoCollection)
+            {
+                var originalPath = item.OriginalPath.ToDelimitedList();
+                var originalParentId = originalPath.Count > 2
+                    ? int.Parse(originalPath[originalPath.Count - 2])
+                    : Constants.System.Root;
+
+                // Add a relation for the item being deleted, so that we can know the original parent for if we need to restore later
+                var relation = new Relation(originalParentId, item.Entity.Id, relationType);
+                relationService.Save(relation);
+
+                Audit.Add(AuditTypes.Delete, string.Format("Trashed content with Id: '{0}' related to original parent content with Id: '{1}'", item.Entity.Id, originalParentId), item.Entity.WriterId, item.Entity.Id);
+            }
+        }
+    }
+}

src/Umbraco.Web/Umbraco.Web.csproj

@@ -494,6 +494,7 @@
     <Compile Include="Mvc\UmbracoVirtualNodeRouteHandler.cs" />
     <Compile Include="Routing\CustomRouteUrlProvider.cs" />
     <Compile Include="Routing\UrlProviderExtensions.cs" />
+    <Compile Include="Strategies\RelateOnTrashHandler.cs" />
     <Compile Include="Strategies\Migrations\ClearCsrfCookiesAfterUpgrade.cs" />
     <Compile Include="Strategies\Migrations\ClearMediaXmlCacheForDeletedItemsAfterUpgrade.cs" />
     <Compile Include="Strategies\Migrations\EnsureListViewDataTypeIsCreated.cs" />