Email has been sent separately to attach the file via email to keep the confidentiality of the contents.

Okay, considering there is a chance this.Item will not be modified but one of its related entities (e.g. this.Item.Details). In this scenario, the entities.OfType<Item>() will return null. Which means it will not enter the foreach loop, in return any chance of getting the original data from related entities is not possible. You can add the LargeImage and ThumbnailImage properties to this.Item, but these properties are useless if there aren't any changes to the entity fields. Using entities.OfType<Details>() will not return null; however, you can't use this with this.GetSingle(IEntity item) to get the original data, because the method is tied to the parent entity, which is this.Item.

Okay, so here's what we did... we extended the auto-generated repository using a partial class and have overriden the InitializeSaveRequest. However, the InitializeSaveRequest method skips the call on foreach loop on save but the data is being saved. Except of course for the image files.

    public class TicketMachineEditViewModel : DataEditorViewModelBase<TicketMachine, ITicketMachineRepository>

Below is the extended repository:

    public partial class TicketMachineRepository
    {
        protected override void InitializeSaveRequest(RestRequest request, IEnumerable<IEntity> entities)
        {
            var p_Items = entities.OfType<TicketMachine>();

            foreach (var p_Item in p_Items)
            {
                var p_OriginalItem = this.GetSingle(p_Item.TicketMachineId);
                var p_Machine = p_OriginalItem.Machine.MachineDetails;

                if (p_Machine.ThumbnailImage != null)
                    request.AddFile("Thumbnail", p_Machine.ThumbnailImage, p_Machine.Photo, "image/jpg");

                if (p_Machine.LargeImage != null)
                    request.AddFile("Large", p_Machine.LargeImage, p_Machine.Photo, "image/jpg");
            }
        }
    }

Please review and see if there's something missing. Both controller and repository files were generated using Intersoft Web API EDM Extensions.