public void EditCharacteristics(string id, string charName, string charValue, string oldN, string oldV)
        {
            MongodbFunctions mongo = new MongodbFunctions();

            ObjectId objID = new ObjectId(id);

            Databases.DomainModel.Product product = mongo.GetProduct(objID);

            List <string> chars   = product.Characteristics;
            string        newChar = charName + ":" + charValue;

            if (oldN.Equals("") || oldV.Equals(""))
            {
                chars.Add(newChar);
            }
            else
            {
                int index = chars.IndexOf(oldN + ":" + oldV);
                chars.RemoveAt(index);
                chars.Insert(index, newChar);
            }

            mongo.UpdateCharacteristics(objID, chars);
        }