type
  TModifyActionList = (lnNone, lnAdded, lnChange, lnDelete);

  TDegree = class
  private
    FOnChange : TNotifyEvent;
    FOnDelete : TNotifyEvent;
    FModifyAction : TModifyActionList;
    FID : Integer;
    FDegree : string;
    procedure SetID(const Value: Integer);
    procedure SetDegree(const Value: string);
  public
    property ID : Integer read FID write SetID;
    property Degree : string read FDegree write SetDegree;
    property ModifyAction : TModifyActionList read FModifyAction write FModifyAction;
    property OnChange : TNotifyEvent read FOnChange write FOnChange;
    property OnDelete : TNotifyEvent read FOnDelete write FOnDelete;
  end;

  TCustomObjectList<T: class> = class(TObjectList<T>)
  private
    FOnChange : TNotifyEvent;
    FOnDelete : TNotifyEvent;
    FModifyAction : TModifyActionList;
    FNewRecord : Boolean;
    procedure DeleteRecord(Klasse: T);
  protected
    function getItem(Index: Integer): T; virtual;
    procedure setItem(Index: Integer; Objekt: T); virtual;
    procedure Notify(const Item: T; Action: TCollectionNotification); override;
  public
    function Add(Objekt: T): Integer; virtual;
    function NewRecord(Objekt: T): Integer; virtual;
    function Remove(Objekt: T): Integer; virtual;
    function IndexOf(Objekt: T): Integer; virtual;
    procedure Insert(Index: Integer; Objekt: T); virtual;
    property Items[index: Integer]: T read getItem write setItem; default;
    property ModifyAction : TModifyActionList read FModifyAction write FModifyAction;
    property OnChange : TNotifyEvent read FOnChange write FOnChange;
    property OnDelete : TNotifyEvent read FOnDelete write FOnDelete;
  end;

{...}

{ TDegree }

procedure TDegree.SetDegree(const Value: string);
begin
  FDegree := Value;
  if (Assigned(FOnChange)) and (FModifyAction = lnChange) then
    FOnChange(Self);
end;

procedure TDegree.SetID(const Value: Integer);
begin
  FID := Value;
  if (Assigned(FOnChange)) and (FModifyAction = lnChange) then
    FOnChange(Self);
end;

{ TCustomObjectList<T> }

function TCustomObjectList<T>.Add(Objekt: T): Integer;
begin
  FNewRecord := False;
  Result := inherited Add(Objekt);
end;

procedure TCustomObjectList<T>.DeleteRecord(Klasse: T);
begin
  // To do something
end;

function TCustomObjectList<T>.getItem(Index: Integer): T;
begin
  Result := T(inherited Items[Index]);
end;

function TCustomObjectList<T>.IndexOf(Objekt: T): Integer;
begin
  Result := inherited IndexOf(Objekt);
end;

procedure TCustomObjectList<T>.Insert(Index: Integer; Objekt: T);
begin
  inherited Insert(Index, Objekt);
end;

function TCustomObjectList<T>.NewRecord(Objekt: T): Integer;
begin
  FNewRecord := True;
  Result := inherited Add(Objekt);
end;

procedure TCustomObjectList<T>.Notify(const Item: T;
  Action: TCollectionNotification);
begin
  if (Assigned(FOnChange)) and (FNewRecord) and (Action <> cnRemoved) then
  begin
    FNewRecord := False;
    FOnChange(Self);
  end;
  if Action = cnRemoved then
  begin
    FOnDelete(Item);
  end;
  inherited Notify(Item, Action);
end;

function TCustomObjectList<T>.Remove(Objekt: T): Integer;
begin
  Result := inherited Remove(Objekt);
end;

procedure TCustomObjectList<T>.setItem(Index: Integer; Objekt: T);
begin
  inherited Items[Index] := Objekt;
end;