#18749: Fixing content part based field alternates

Work Item: 18749

--HG--
branch : 1.x

src/Orchard/ContentManagement/Drivers/ContentFieldDriver.cs

@@ -148,7 +148,7 @@ namespace Orchard.ContentManagement.Drivers {
 
             var shapeType = metadata.Type;
             var fieldName = differentiator ?? String.Empty;
-            string partName = shape.ContentPart.PartDefinition.Name;
+            string partName = ctx.ContentPart.PartDefinition.Name;
             string contentType = shape.ContentItem.ContentType;
 
             // whether the content type has been created dynamically or not

src/Orchard/ContentManagement/Drivers/ContentShapeResult.cs

@@ -34,12 +34,16 @@ namespace Orchard.ContentManagement.Drivers {
                 return;
 
             dynamic parentShape = context.Shape;
+            context.ContentPart = ContentPart;
+
             var newShape = _shapeBuilder(context);
 
+            // add a ContentPart property to the final shape 
             if (ContentPart != null && newShape.ContentPart == null) {
                 newShape.ContentPart = ContentPart;
             }
 
+            // add a ContentField property to the final shape 
             if (ContentField != null && newShape.ContentField == null) {
                 newShape.ContentField = ContentField;
             }

src/Orchard/ContentManagement/Handlers/BuildShapeContext.cs

@@ -18,6 +18,7 @@ namespace Orchard.ContentManagement.Handlers {
         public ContentItem ContentItem { get; private set; }
         public dynamic New { get; private set; }
         public string GroupId { get; private set; }
+        public ContentPart ContentPart { get; set; }
 
         public Func<string, string, string, PlacementInfo> FindPlacement { get; set; }
     }