/// <summary>
 /// Method to add retailstore details to the list
 /// </summary>
 /// <param name="retailstoreDetails">represents the details of retailstore eg</param>
 public static void AddRetailStore(Retailstore retailstoreDetails)
 {
     //condtion for checking wheather the retailstore id exists or not
     if (retailstoreDetails.RetailCustomerID != null)
     {
         _retailStoreList.Add(retailstoreDetails);
         // SaveIntoFile();
     }
     else
     {
         throw new RetailstoreException("Already exists");
     }
 }
 /// <summary>
 /// method to Update the customername
 /// </summary>
 /// <param name="retailstore">represents retailstore object</param>
 public void UpdateRetailstoreByRetailCustomerID(Retailstore retailstore)
 {
     try
     {
         if (retailstore.RetailCustomerID != null)
         {
             _retailStoreDataAccessLayer.UpdateRetailstoreByRetailCustomerID(retailstore);
         }
     }
     catch (RetailstoreException ex)
     {
         throw new RetailstoreException(ex.Message);
     }
 }
 /// <summary>
 /// Method to add retail store details
 /// </summary>
 /// <param name="r">represents the retail store object</param>
 public void AddRetailstore(Retailstore r)
 {
     try
     {
         //Retail customer id not be null
         if (r.RetailCustomerID != null)
         {
             //RetailStoreDataAccessLayer.AddRetailStore(r);
         }
     }
     catch (RetailstoreException ex)
     {
         throw new RetailstoreException(ex.Message);
     }
 }
        /// <summary>
        /// Method to update the customername
        /// </summary>
        /// <param name="retailstore">Reprsents the retailstore object</param>
        public void UpdateRetailstoreByRetailCustomerID(Retailstore retailstore)
        {
            //if (_retailStoreList.Exists(r => r.RetailCustomerID == retailstore.RetailCustomerID))

            Retailstore u = _retailStoreList.Find(r => r.RetailCustomerID == retailstore.RetailCustomerID);

            if (u != null)
            {
                u.CustomerName = retailstore.CustomerName;
                // SaveIntoFile();
            }

            else
            {
                throw new RetailstoreException("Retailstore doesn't exist");
            }
        }