GazpromApp/Utils/PropertyParentHelper.cs

using GazpromApp.Models;
using System.Collections.Generic;
using System.Linq;

namespace GazpromApp.Utils
{
    public static class PropertyParentHelper
    {
        public static void SetPropertyParents(this Point point)
        {
            // Set parents for properties in point
            foreach (var prop in point.Properties)
            {
                SetParentsRecursively(prop);
            }

            // Set parents for properties in equipment
            foreach (var prop in point.Equipment.SelectMany(equipment => equipment.Properties))
            {
                SetParentsRecursively(prop);
            }
        }

        private static void SetParentsRecursively(Property property)
        {
            foreach (var childProp in property.Properties)
            {
                childProp.Parent = property;
                childProp.ParentId = property.Id;
                SetParentsRecursively(childProp);
            }
        }
    }
}