builder.Services.AddDbContext<ApplicationDbContext>(options =>
 options.UseSqlServer(builder.Configuration.GetConnectionString("DefaultConnection")));

 builder.Services.AddDbContext<ApplicationDbContext>(options =>
 options.UseSqlServer(builder.Configuration.GetConnectionString("DefaultConnection")));

System.AggregateException: 'Some services are not able to be constructed (Error while validating the service descriptor 'ServiceType: UserServices.Interface.IDepartmentRepository Lifetime: Scoped ImplementationType: UserServices.Repositories.DepartmentRepository': Unable to resolve service for type 'Microsoft.EntityFrameworkCore.DbContext' while attempting to activate 'UserServices.Repositories.DepartmentRepository'.)'

System.AggregateException: 'Some services are not able to be constructed (Error while validating the service descriptor 'ServiceType: UserServices.Interface.IDepartmentRepository Lifetime: Scoped ImplementationType: UserServices.Repositories.DepartmentRepository': Unable to resolve service for type 'Microsoft.EntityFrameworkCore.DbContext' while attempting to activate 'UserServices.Repositories.DepartmentRepository'.)'

 /// <summary>
    /// The 'Base' abstract class
    /// </summary>
    public abstract class DeliverySystem

    {

        private StandardDeliveryContext standardDeliveryContext;

        public DeliverySystem(StandardDeliveryContext _standardDeliveryContext)
        {

            this.standardDeliveryContext = _standardDeliveryContext;

        }


    }

 /// <summary>
    /// The 'Base' abstract class
    /// </summary>
    public abstract class DeliverySystem

    {

        private StandardDeliveryContext standardDeliveryContext;

        public DeliverySystem(StandardDeliveryContext _standardDeliveryContext)
        {

            this.standardDeliveryContext = _standardDeliveryContext;

        }


    }

  public class Delivered : DeliverySystem, IOrderState

    {

        private readonly StandardDeliveryContext standardDelivery;
        public DateTime deliveryDate { get; set; }


        public Delivered(StandardDeliveryContext _standardDelivery) : base(_standardDelivery)
        {

            this.standardDelivery = _standardDelivery;

        }


        public DateTime PreparedOrder(DateTime placedOrderDate)
        {
            throw new NotImplementedException("Data");
        }

        public DateTime DispatchOrder(DateTime placedOrderDate)
        {
            throw new NotImplementedException("Data");
        }
        public DateTime DeliveredOrder(DateTime placedOrderDate)
        {
            standardDelivery.State = StandardDeliveryState.Delivered;
           // placedOrderDate = standardDelivery.placedOrderDate.AddDays(1);
            return placedOrderDate.AddDays(1);
        }
    }

  public class Delivered : DeliverySystem, IOrderState

    {

        private readonly StandardDeliveryContext standardDelivery;
        public DateTime deliveryDate { get; set; }


        public Delivered(StandardDeliveryContext _standardDelivery) : base(_standardDelivery)
        {

            this.standardDelivery = _standardDelivery;

        }


        public DateTime PreparedOrder(DateTime placedOrderDate)
        {
            throw new NotImplementedException("Data");
        }

        public DateTime DispatchOrder(DateTime placedOrderDate)
        {
            throw new NotImplementedException("Data");
        }
        public DateTime DeliveredOrder(DateTime placedOrderDate)
        {
            standardDelivery.State = StandardDeliveryState.Delivered;
           // placedOrderDate = standardDelivery.placedOrderDate.AddDays(1);
            return placedOrderDate.AddDays(1);
        }
    }

 public class Dispatched : DeliverySystem, IOrderState

    {

        private readonly StandardDeliveryContext standardDelivery;
        public DateTime dispatchDate { get; set; }


        public Dispatched(StandardDeliveryContext _standardDelivery) : base(_standardDelivery)

        {

            this.standardDelivery = _standardDelivery;

        }


        public DateTime PreparedOrder(DateTime placedOrderDate)
        {
            throw new NotImplementedException("Data");
        }

        public DateTime DispatchOrder(DateTime placedOrderDate)
        {
            standardDelivery.State = StandardDeliveryState.Dispatched;
            //standardDelivery.placedOrderDate = standardDelivery.placedOrderDate.AddDays(1);
            return placedOrderDate.AddDays(1);
        }
        public DateTime DeliveredOrder(DateTime placedOrderDate)
        {
            throw new NotImplementedException("Data");
        }
    }

 public class Dispatched : DeliverySystem, IOrderState

    {

        private readonly StandardDeliveryContext standardDelivery;
        public DateTime dispatchDate { get; set; }


        public Dispatched(StandardDeliveryContext _standardDelivery) : base(_standardDelivery)

        {

            this.standardDelivery = _standardDelivery;

        }


        public DateTime PreparedOrder(DateTime placedOrderDate)
        {
            throw new NotImplementedException("Data");
        }

        public DateTime DispatchOrder(DateTime placedOrderDate)
        {
            standardDelivery.State = StandardDeliveryState.Dispatched;
            //standardDelivery.placedOrderDate = standardDelivery.placedOrderDate.AddDays(1);
            return placedOrderDate.AddDays(1);
        }
        public DateTime DeliveredOrder(DateTime placedOrderDate)
        {
            throw new NotImplementedException("Data");
        }
    }

 public class Prepared : DeliverySystem, IOrderState

    {

        private readonly StandardDeliveryContext standardDelivery;
        public DateTime preparedDate { get; set; }


        public Prepared(StandardDeliveryContext _standardDelivery) : base(_standardDelivery)

        {

            this.standardDelivery = _standardDelivery;

        }


        public DateTime PreparedOrder(DateTime placedOrderDate)
        {
            standardDelivery.State = StandardDeliveryState.Prepared;
           // standardDelivery.placedOrderDate = standardDelivery.placedOrderDate.AddDays(1);
            return placedOrderDate.AddDays(1);
        }

        public DateTime DispatchOrder(DateTime placedOrderDate)
        {
            throw new NotImplementedException("Data");
        }


        public DateTime DeliveredOrder(DateTime placedOrderDate)
        {
            throw new NotImplementedException("Data");
        }
    }

 public class Prepared : DeliverySystem, IOrderState

    {

        private readonly StandardDeliveryContext standardDelivery;
        public DateTime preparedDate { get; set; }


        public Prepared(StandardDeliveryContext _standardDelivery) : base(_standardDelivery)

        {

            this.standardDelivery = _standardDelivery;

        }


        public DateTime PreparedOrder(DateTime placedOrderDate)
        {
            standardDelivery.State = StandardDeliveryState.Prepared;
           // standardDelivery.placedOrderDate = standardDelivery.placedOrderDate.AddDays(1);
            return placedOrderDate.AddDays(1);
        }

        public DateTime DispatchOrder(DateTime placedOrderDate)
        {
            throw new NotImplementedException("Data");
        }


        public DateTime DeliveredOrder(DateTime placedOrderDate)
        {
            throw new NotImplementedException("Data");
        }
    }

  public enum StandardDeliveryState
    {
        Placed,
        Prepared,
        Dispatched,
        Delivered,
    }

    public class StandardDeliveryContext: IOrderState
    {
        public static OrderRepository OrderRepository { get; set; }

        public static void Init(OrderRepository _orderRepository)

        {

            OrderRepository = _orderRepository;

        }


        public int customerId { get; set; }

        public int orderId { get; set; }

        public DateTime placedOrderDate { get; set; }

        private IOrderState process;

        private StandardDeliveryState state;
        public StandardDeliveryState State
        {
            get => state;
            set
            {
                state = value;

                switch (state)
                {

                    case StandardDeliveryState.Placed:
                        process = new PreparedOrder(this);
                        break;

                    case StandardDeliveryState.Dispatched:
                        process = new DispatchOrder(this);
                        break;

                    case StandardDeliveryState.Delivered:
                        process = new Delivered(this);
                        break;
                }
            }
        }

        public void PreparedOrder(this)
        {
            process.PreparedOrder(placedOrderDate);
        }

        public void DispatchOrder(DateTime placedOrderDate)
        {
            process.DispatchOrder(placedOrderDate);
        }
        public void Delivered(DateTime placedOrderDate)
        {
            process.Delivered(placedOrderDate);
        }
    }

  public enum StandardDeliveryState
    {
        Placed,
        Prepared,
        Dispatched,
        Delivered,
    }

    public class StandardDeliveryContext: IOrderState
    {
        public static OrderRepository OrderRepository { get; set; }

        public static void Init(OrderRepository _orderRepository)

        {

            OrderRepository = _orderRepository;

        }


        public int customerId { get; set; }

        public int orderId { get; set; }

        public DateTime placedOrderDate { get; set; }

        private IOrderState process;

        private StandardDeliveryState state;
        public StandardDeliveryState State
        {
            get => state;
            set
            {
                state = value;

                switch (state)
                {

                    case StandardDeliveryState.Placed:
                        process = new PreparedOrder(this);
                        break;

                    case StandardDeliveryState.Dispatched:
                        process = new DispatchOrder(this);
                        break;

                    case StandardDeliveryState.Delivered:
                        process = new Delivered(this);
                        break;
                }
            }
        }

        public void PreparedOrder(this)
        {
            process.PreparedOrder(placedOrderDate);
        }

        public void DispatchOrder(DateTime placedOrderDate)
        {
            process.DispatchOrder(placedOrderDate);
        }
        public void Delivered(DateTime placedOrderDate)
        {
            process.Delivered(placedOrderDate);
        }
    }

 public interface IOrderState
    {
        DateTime PreparedOrder(DateTime orderDate);
        DateTime DispatchOrder(DateTime preparedDate);
        DateTime Delivered(DateTime dispatchDate);

    }

 public interface IOrderState
    {
        DateTime PreparedOrder(DateTime orderDate);
        DateTime DispatchOrder(DateTime preparedDate);
        DateTime Delivered(DateTime dispatchDate);

    }