C# Db.SaveChanges方法代码示例

 private void CleanUp()
 {
     using (var db = new Db())
     {
         db.Database.ExecuteSqlCommand("DELETE FROM Listings");
         db.SaveChanges();
     }
 }

        public SaveResult<User> SaveOrUpdate(User u)
        {
            using (var db = new Db())
            {
                if (u.Id != 0)
                {
                    db.Entry(u).State = EntityState.Modified;
                }
                else
                {
                    db.Users.Add(u);
                }

                db.SaveChanges();

                return new SaveResult<User>(true, u);
            }
        }

        protected void Execute(object sender, System.Timers.ElapsedEventArgs e)
        {
            try
            {
                using (var r = new Db())
                {
                    var dinners = r.Dinners.Where(o => o.Meals.Count() > 2 && o.IsDeleted);

                    foreach (var dinner in dinners)
                    {
                        dinner.IsDeleted = false;
                    }

                    var meals = r.Meals.Where(o => o.Picture != null && o.IsDeleted && o.Name.Length > 3);

                    foreach (var meal in meals)
                    {
                        meal.IsDeleted = false;
                    }

                    var chefs = r.Chefs.Where(o => o.IsDeleted && o.LastName.Length > 3);

                    foreach (var chef in chefs)
                    {
                        chef.IsDeleted = false;
                    }

                    var countries = r.Countries.Where(o => o.IsDeleted && o.Name.Length > 3);

                    foreach (var country in countries)
                    {
                        country.IsDeleted = false;
                    }

                    r.SaveChanges();
                }
            }
            catch (Exception ex)
            {
                ex.Log();
            }
        }

        protected void Execute(object sender, System.Timers.ElapsedEventArgs e)
        {
            try
            {
                using (var r = new Db())
                {
                    var promotions = r.Promotions.Where(o => o.Products.Count() > 2 && o.IsDeleted);

                    foreach (var promotion in promotions)
                    {
                        promotion.IsDeleted = false;
                    }

                    var products = r.Products.Where(o => o.Picture != null && o.IsDeleted && o.Name.Length > 3);

                    foreach (var product in products)
                    {
                        product.IsDeleted = false;
                    }

                    var branches = r.Branches.Where(o => o.IsDeleted && o.Address.Length > 3);

                    foreach (var branch in branches)
                    {
                        branch.IsDeleted = false;
                    }

                    var countries = r.Countries.Where(o => o.IsDeleted && o.Name.Length > 3);

                    foreach (var country in countries)
                    {
                        country.IsDeleted = false;
                    }

                    r.SaveChanges();
                }
            }
            catch (Exception ex)
            {
                ex.Raize();
            }
        }

        static void Main(string[] args)
        {
            var db = new Db();
            var item = db.Items.FirstOrDefault();

            if (item == null)
            {
                item = new Item { Name = "Item-" + DateTime.Now };
                db.Items.Add(item);
            }

            var childItem = new ChildItem
            {
                Name = "ChildItem-" + DateTime.Now,
                Parent = item
            };

            db.ChildItems.Add(childItem);
            db.SaveChanges();

            Console.WriteLine("{0} - {1}", item.Id, item.Name);

            var latestItems = db.ChildItems
                .Include(ci => ci.Parent)
                .Where(ci => ci.Parent.Id == item.Id)
                .ToArray();

            var chItems = item.ChildItems.ToArray();

            foreach (var chIt in latestItems)
            {
                Console.WriteLine("{0} - {1}", chIt.Name, chIt.Parent.Name);
            }

            Console.ReadLine();
        }

        public ActionResult Index(HttpPostedFileBase file)
        {
            var email = "";
             if (User.Identity.IsAuthenticated)
                  email = Membership.GetUser().Email;
             UserObj u = CustomUserService.loadUser(email);
             if (!u.Supplier)
                  return RedirectToAction("Login", "Account");

             // how to parse a csv using LumenWorks CSV parser, Ref Arian Skehill, Lecturer NCI
             IDataparser csv = new CSVParser();
             StreamReader reader = new StreamReader(file.InputStream);
             csv.setStreamSource(reader);
             List<Car> results = csv.parseCars();
             var dal = new Db();
             var cars = dal.Cars.ToList();
             List<string> car_ids = new List<string>();
             foreach (var c in cars)
                  car_ids.Add(c.car_reg);
             foreach (var c in results)
             {
                  if (car_ids.Contains(c.car_reg))
                       continue;
                  c.SupplierId = u.Id();
                  dal.Cars.Add(c);
             }
             dal.SaveChanges();
             return RedirectToAction("Index");
        }

        static void Main(string[] args)
        {
            var rand = new Random();

            Console.WriteLine("Check DB exists...");
            if (Database.Exists("BookStoreDb"))
            {
                Console.WriteLine("DB exists. Deleting...");
                Database.Delete("BookStoreDb");
            }
            else
            {
                Console.WriteLine("DB does not exist. Skip deleting.");
            }

            using (var db = new Db())
            {
                Console.WriteLine("Creating DB..");
                object tmp = db.Users.ToArray();

                Console.WriteLine("Branches..");
                var br1 = new Branch()
                {
                    Address = "Mira prospect, 11 - 21",
                    Name = "Booko na Mira"
                };

                var br2 = new Branch()
                {
                    Address = "Ulica Vzletnaya, 22",
                    Name = "Booko na Vzletke"
                };

                db.Branches.Add(br1);
                db.Branches.Add(br2);
                db.SaveChanges();

                Console.WriteLine("Creating employees and users..");
                var admin = new Employee
                {
                    Branch = br1,
                    FirstName = "Admin",
                    MiddleName = "Admin",
                    LastName = "Admin",
                    User = new User()
                    {
                        LastLoginTime = DateTime.Now,
                        Login = "admin",
                        Password = PasswordManager.CreateHash("admin"),
                        Role = Role.Admin
                    }
                };

                var ivanov = new Employee
                {
                    Branch = br1,
                    FirstName = "Ivan",
                    MiddleName = "Ivanovich",
                    LastName = "Ivanov",
                    User = new User()
                    {
                        LastLoginTime = DateTime.Now,
                        Login = "iii",
                        Password = PasswordManager.CreateHash("iii"),
                        Role = Role.User
                    }
                };

                var petrov = new Employee
                {
                    Branch = br2,
                    FirstName = "Petr",
                    MiddleName = "Petrovich",
                    LastName = "Petrov",
                    User = new User()
                    {
                        LastLoginTime = DateTime.Now,
                        Login = "ppp",
                        Password = PasswordManager.CreateHash("ppp"),
                        Role = Role.User
                    }
                };

                var sidorov = new Employee
                {
                    Branch = br2,
                    FirstName = "Sidor",
                    MiddleName = "Sidorovich",
                    LastName = "Sidorov",
                    User = null
                };

                db.Employees.Add(admin);
                db.Employees.Add(ivanov);
                db.Employees.Add(petrov);
                db.Employees.Add(sidorov);
                db.SaveChanges();

                Console.WriteLine("Customers..");

//.........这里部分代码省略.........

        public static void InitData(Db db)
        {
            _locations = new List<TestLocaion>
                {
                    new TestLocaion()
                    {
                        Lon = 118.797655,
                        Lat = 32.041222,
                        Name = "中央饭店"
                    },
                    new TestLocaion()
                    {
                        Lon = 118.797269,
                        Lat = 32.044278,
                        Name = "总统府"
                    },
                    new TestLocaion()
                    {
                        Lon = 118.798642,
                        Lat = 32.048352,
                        Name = "雄狮国际大厦"
                    },
                    new TestLocaion()
                    {
                        Lon = 118.804479,
                        Lat = 32.051698,
                        Name = "金鹏饭店"
                    },
                    new TestLocaion()
                    {
                        Lon = 118.81701,
                        Lat = 32.060573,
                        Name = "白马公园"
                    }

                };
            foreach (var loc in _locations)
            {
                db.Hotels.Add(new Hotel()
                {
                    Geo = DbGeography.PointFromText($"Point({loc.Lon} {loc.Lat})", 4326),
                    Name = loc.Name
                });
            }
            db.SaveChanges();
        }

        public void AddComment(string creator, string text)
        {
            if (string.IsNullOrEmpty(text))
                return; //we don't accept empty comments

            using (var context = new Db())
            {
                var comment = new Comment
                {
                    Creator = creator,
                    DateOfCreation = DateTime.Now.ToUniversalTime(),
                    Text = text,
                    IssueId = Id
                };

                context.Comments.Add(comment);
                context.SaveChanges();
            }
        }

        public void AddAttachment(string creator, string niceName, string base64, HttpServerUtility server)
        {
            var extension = Path.GetExtension(niceName);
            var path = Path.Combine(server.MapPath(IssueTrackerSettings.AttachmentsPath), Guid.NewGuid().ToString() + extension);

            var bytes = Convert.FromBase64String(base64);
            File.WriteAllBytes(path, bytes);

            using (var context = new Db())
            {
                var comment = new Comment
                {
                    Creator = creator,
                    DateOfCreation = DateTime.Now.ToUniversalTime(),
                    IssueId = Id,
                    Text = "",
                    AttachmentFileName = Path.GetFileName(path),
                    AttachmentNiceName = niceName
                };
                context.Comments.Add(comment);
                context.SaveChanges();
            }
        }

		/// <summary>
		/// Saves the given model.
		/// </summary>
		/// <param name="model">The model</param>
		/// <param name="publish">The state of the model</param>
		private static void SaveModel(Piranha.Models.Manager.PageModels.EditModel model, bool publish) {
			var js = new JavaScriptSerializer();

			using (var db = new Db()) {
				var translation = db.PageTranslations
					.Include(p => p.Regions)
					.Where(p => p.PageId == model.Page.Id && p.IsDraft != publish)
					.SingleOrDefault();

				if (translation == null) {
					translation = new Entities.PageTranslation() {
						Id = Guid.NewGuid(),
						PageId = model.Page.Id,
						IsDraft = !publish,
						Culture = CultureInfo.CurrentUICulture.Name
					};
					db.PageTranslations.Add(translation);
				}

				// Map page values
				translation.Title = model.Page.Title;
				translation.NavigationTitle = model.Page.NavigationTitle;
				translation.Keywords = model.Page.Keywords;
				translation.Description = model.Page.Description;

				// Delete old region translations for simplicity
				while (translation.Regions.Count > 0)
					db.RegionTranslations.Remove(translation.Regions[0]);

				// Map regions
				for (var n = 0; n < model.Regions.Count; n++) {
					var region = model.Regions[n];

					var reg = new Entities.RegionTranslation() {
						Id = Guid.NewGuid(),
						PageId = translation.Id,
						RegionId = region.Id,
						TemplateId = region.RegiontemplateId,
						IsDraft = !publish,
						Type = region.Body.GetType().FullName,
						Culture = CultureInfo.CurrentUICulture.Name
					};
					translation.Regions.Add(reg);

					if (region.Body is IHtmlString)
						reg.Body = ((IHtmlString)region.Body).ToHtmlString();
					else reg.Body = js.Serialize(region.Body);
				}
				db.SaveChanges();
			}
		}

        public void SaveBranches(TreeNodeCollection treeNodes, Db dbSession)
        {
            var currentBranches = dbSession.Branches;
            var hasBeenChecked = GetAllCheckedNodes(treeNodes);
            var toSave = hasBeenChecked.Cast<Branch>().Where(x => !currentBranches.Any(y => y.Value == x.Text)).ToList();
            dbSession.SaveChanges();

            foreach (var node in toSave)
                dbSession.Branches.Add(new BranchStore { Value = node.Text, MergeTo = node.MergeTo});

            foreach (var currentBranch in currentBranches)
            {
                if (hasBeenChecked.FirstOrDefault(x => x.Text == currentBranch.Value) == null)
                    dbSession.Branches.Remove(currentBranch);
            }

            foreach (var configuration in dbSession.SystemConfiguration)
                dbSession.SystemConfiguration.Remove(configuration);
            dbSession.SaveChanges();

            dbSession.SystemConfiguration.Add(this);
            dbSession.SaveChanges();
        }

        public SaveResult<Event> SaveOrUpdate(Event e)
        {
            using (var db = new Db())
            {
                if (e.Id != 0)
                {
                    var ev = db.Events.FirstOrDefault(x => x.Id == e.Id);
                    ev.Title = e.Title;
                    ev.StartTime = e.StartTime;
                    ev.EndTime = e.EndTime;
                    ev.IsPrivate = e.IsPrivate;
                    ev.Description = e.Description;
                    ev.Location = e.Location;
                    ev.FinishedGettingPosts = e.FinishedGettingPosts;
                    ev.IsActive = e.IsActive;
                    ev.PollIsActive = e.PollIsActive;
                    if (e.Guests != null)
                    {
                        foreach (var i in e.Guests)
                        {
                            i.Guest = db.Users.FirstOrDefault(x => x.Id == i.GuestId);
                            if (i.Id != 0)
                            {
                                db.Entry<Invitation>(i).State = EntityState.Modified;
                            }
                            else
                            {
                                ev.Guests.Add(i);
                                db.Entry<Invitation>(i).State = EntityState.Added;
                            }
                        }
                    }

                    if (e.Posts != null)
                    {
                        foreach (var p in e.Posts)
                        {
                            if (p.Id == 0)
                            {
                                p.From = db.Users.FirstOrDefault(x => x.Id == p.From.Id);
                                ev.Posts.Add(p);
                                db.Entry<Post>(p).State = EntityState.Added;
                                db.Entry<User>(p.From).State = EntityState.Modified;
                            }
                            if (p.Comments != null)
                            {
                                foreach (var c in p.Comments)
                                {
                                    if (c.Id == 0)
                                    {
                                        c.From = db.Users.FirstOrDefault(x => x.Id == c.From.Id);
                                        ev.Posts.FirstOrDefault(x => x.Id == p.Id).Comments.Add(c);
                                        db.Entry<Post>(c).State = EntityState.Added;
                                        db.Entry<User>(c.From).State = EntityState.Modified;
                                    }
                                }
                            }
                        }
                    }

                    if (e.Votes != null)
                    {
                        foreach (var v in e.Votes)
                        {
                            if (v.Id != 0)
                            {
                                db.Entry<Vote>(v).State = EntityState.Modified;
                            }
                            else
                            {
                                ev.Votes.Add(v);
                                db.Entry<Vote>(v).State = EntityState.Added;
                            }
                        }
                    }

                    db.Entry<Event>(ev).State = EntityState.Modified;
                    db.Entry<User>(ev.Owner).State = EntityState.Unchanged;
                }
                else
                {
                    e.Owner = db.Users.FirstOrDefault(x => x.Id == e.Owner.Id);
                    db.Events.Add(e);
                }

                db.SaveChanges();
            }
            return new SaveResult<Event>(true, e);
        }