public async void Save()
        {
            var context = new LiteratureRegisterContext();

            context.Update(Thesis);
            await context.SaveChangesAsync();
        }
        public async void Delete()
        {
            var context = new LiteratureRegisterContext();

            if (context.Theses.Any(x => x.Id == Thesis.Id))
            {
                context.Remove(Thesis);
                await context.SaveChangesAsync();
            }
        }