Updated some of the property editor API to ensure that when formatting data for persistence we have access to the pre-values as well since these might need to be used to format the persisted data. Completed the new property editor: Multiple text box and it is saving the data in a backwards compatible format. Changed the internal AsDictionary method of the pre value collection to be a public method called FormatAsDictionary.

src/Umbraco.Core/Models/Editors/ContentPropertyData.cs

@@ -16,9 +16,10 @@ namespace Umbraco.Core.Models.Editors
     /// </remarks>
     public class ContentPropertyData
     {
-        public ContentPropertyData(object value, IDictionary<string, object> additionalData)
+        public ContentPropertyData(object value, PreValueCollection preValues, IDictionary<string, object> additionalData)
         {
             Value = value;
+            PreValues = preValues;
             AdditionalData = new ReadOnlyDictionary<string, object>(additionalData);
         }
 
@@ -29,6 +30,8 @@ namespace Umbraco.Core.Models.Editors
         /// </summary>
         public object Value { get; private set; }
 
+        public PreValueCollection PreValues { get; private set; }
+
         /// <summary>
         /// A dictionary containing any additional objects that are related to this property when saving
         /// </summary>