public static List <List <UserDefinedCell> > Get(IVisio.Page page, IList <IVisio.Shape> shapes)
        {
            if (page == null)
            {
                throw new System.ArgumentNullException(nameof(page));
            }

            if (shapes == null)
            {
                throw new System.ArgumentNullException(nameof(shapes));
            }

            var shapeids = shapes.Select(s => s.ID).ToList();

            var list_data = UserDefinedCell.GetCells(page, shapeids);

            var list_list = new List <List <UserDefinedCell> >(shapeids.Count);

            for (int i = 0; i < shapes.Count; i++)
            {
                var shape      = shapes[i];
                var shape_data = list_data[i];
                var prop_names = UserDefinedCellHelper.GetNames(shape);

                var list = new List <UserDefinedCell>(shape_data.Count);
                list_list.Add(list);
                for (int j = 0; j < shape_data.Count; j++)
                {
                    shape_data[j].Name = prop_names[j];
                    list.Add(shape_data[j]);
                }
            }

            return(list_list);
        }
        /// <summary>
        /// Gets all the user properties defined on a shape
        /// </summary>
        /// <remarks>
        /// If there are no user properties then null will be returned</remarks>
        /// <param name="shape"></param>
        /// <returns>A list of user  properties</returns>
        public static List <UserDefinedCell> Get(IVisio.Shape shape)
        {
            if (shape == null)
            {
                throw new System.ArgumentNullException(nameof(shape));
            }

            var prop_count = UserDefinedCellHelper.GetCount(shape);

            if (prop_count < 1)
            {
                return(new List <UserDefinedCell>(0));
            }

            var prop_names = UserDefinedCellHelper.GetNames(shape);

            if (prop_names.Count != prop_count)
            {
                throw new InternalAssertionException("Unexpected number of prop names");
            }

            var shape_data = UserDefinedCell.GetCells(shape);

            var list = new List <UserDefinedCell>(prop_count);

            for (int i = 0; i < prop_count; i++)
            {
                shape_data[i].Name = prop_names[i];
                list.Add(shape_data[i]);
            }

            return(list);
        }