C# DataContext类代码示例

        public async Task SetupAsync()
        {
            _evnt = new EventViewModel
            {
                Title = "Title event",
                Description = "Test event",
                Start = "11:00",
                End = "14:27",
                Date = "2016-02-01"
            };

            var userViewModel = new LoginViewModel
            {
                Email = "[email protected]",
                Password = "useruser",
                RememberMe = false
            };
            var context = new DataContext();
            var manager = new UserManager(new UserStore(context));
            var user = await manager.FindAsync(userViewModel.Email, userViewModel.Password);
            if (user == null)
            {
                await manager.CreateAsync(new User { Email = userViewModel.Email, UserName = userViewModel.Email }, userViewModel.Password);
            }
            _calendarController = new CalendarController(context);

            var mockCp = new Mock<IClaimsPrincipal>();
            if (user != null) mockCp.SetupGet(cp => cp.UserId).Returns(user.Id);
            _calendarController.CurrentUser = mockCp.Object;

            var mockAuthenticationManager = new Mock<IAuthenticationManager>();
            mockAuthenticationManager.Setup(am => am.SignOut());
            mockAuthenticationManager.Setup(am => am.SignIn());
            _calendarController.AuthenticationManager = mockAuthenticationManager.Object;
        }

        static void Main(string[] args)
        {
            DataContext dc = new DataContext(@"Data Source=.\SQLEXPRESS;Initial Catalog=AdventureWorks;Integrated Security=True");

            dc.Log = Console.Out;

            //Table<Pessoa> pessoas = dc.GetTable<Pessoa>();

            var pessoas = from p in dc.GetTable<Pessoa>()
                          select p;

            //ObjectDumper.Write(pessoas);

            //Console.WriteLine();

            var nomes = from p in pessoas
                        select p.Nome;

            nomes = from p in nomes
                    where p.Equals("ABEL")
                    select p;

            ObjectDumper.Write(nomes);

            Console.ReadKey();
        }

        /// <summary>
        /// Constructor initializes DataContext 
        /// plus adds additional configuration
        /// </summary>
        public RepositoryBase()
        {
            dc = new DataContext();

            dc.Configuration.LazyLoadingEnabled = false;
            dc.Configuration.ProxyCreationEnabled = false;
        }

        public async Task<ActionResult> Login(LoginViewModel model, string returnUrl)
        {
            if (!ModelState.IsValid)
            {
                using (var db = new DataContext())
                {
                    ViewBag.LoginsList = db.Users.ToArray();
                }

                return View(model);
            }

            // This doesn't count login failures towards account lockout
            // To enable password failures to trigger account lockout, change to shouldLockout: true
            var result = await SignInManager.PasswordSignInAsync(model.UserName, model.Password, model.RememberMe, shouldLockout: false);
            switch (result)
            {
                case SignInStatus.Success:
                    return RedirectToLocal(returnUrl);
                case SignInStatus.LockedOut:
                    return View("Lockout");
                case SignInStatus.RequiresVerification:
                    return RedirectToAction("SendCode", new { ReturnUrl = returnUrl, RememberMe = model.RememberMe });
                case SignInStatus.Failure:
                default:
                    ModelState.AddModelError("", "Invalid login attempt.");
                    return View(model);
            }
        }

        private void AddOrUpdate(List<ExcelDeltaker> deltakere, DataContext context)
        {
            var alleLag = context.Lag.ToList();

            foreach (var excelDeltaker in deltakere)
            {
                var deltaker = context.Deltakere.SingleOrDefault(x => x.Kode == excelDeltaker.Kode);

                var lag = alleLag.SingleOrDefault(x => x.LagId == excelDeltaker.LagId);

                if (deltaker == null)
                {
                    context.Deltakere.Add(new Deltaker
                    {
                        DeltakerId = Guid.NewGuid().ToString(),
                        Navn = excelDeltaker.Navn,
                        Kode = excelDeltaker.Kode,
                        Lag = lag
                    });
                }
                else
                {
                    deltaker.Navn = excelDeltaker.Navn;
                    deltaker.Lag = lag;
                }
            }
        }

        //private static TextWriter dbLinqLogWriter = new StreamWriter(@"C:\Temp\sipsorcery\dblinq.log", true, Encoding.ASCII);

        public static DataContext CreateDBLinqDataContext(StorageTypes storageType, string connectionString) {
            DataContext dataContext = null;
            //DbProviderFactory factory = DbProviderFactories.GetFactory(providerName);
            //new MySql.Data.MySqlClient.MySqlClientFactory();
            //DbProviderFactory factory = Npgsql.NpgsqlFactory.Instance;
            
            switch (storageType) {
                case StorageTypes.DBLinqMySQL:
                    IDbConnection mySqlConn = new MySqlConnection(connectionString);
                    dataContext = new DataContext(mySqlConn, m_mappingSource, new DbLinq.MySql.MySqlVendor());
                    break;
                case StorageTypes.DBLinqPostgresql:
                    IDbConnection npgsqlConn = new NpgsqlConnection(connectionString);
                    dataContext = new DataContext(npgsqlConn, m_mappingSource, new DbLinq.PostgreSql.PgsqlVendor());
                    break;
                default:
                    throw new NotSupportedException("Database type " + storageType + " is not supported by CreateDBLinqDataContext.");
            }

            //dataContext.QueryCacheEnabled = true;
            //dataContext.Log = Console.Out;
            //dataContext.Log = dbLinqLogWriter;
            dataContext.ObjectTrackingEnabled = false;
            return dataContext;
        }

        public EventCategorySingleViewModel(string category, HttpServerUtilityBase server)
        {
            _server = server;

            category = formatCategoryString(category);

            //ImageList = getImageList();

            using (var context = new DataContext())
            {
                var tomorrow = DateTime.Now.Date;
                TheCategory = context.EventCategories.FirstOrDefault(x => x.CategoryName == category);

                EventRoll = context.Events.Where(x => x.MainCategory == category && x.IsActive == true && DateTime.Compare(x.EndDate.Value, tomorrow) >= 0).ToList();

                // Set a random picture on the eventRoll if none is currently set
                //foreach (var event in EventRoll)
                //{
                //	if (String.IsNullOrEmpty(event.ImageUrl))
                //	{
                //		event.ImageUrl = getRandomImage();
                //	}

                //}
            }
        }

        /// <summary>
        /// Creates a new site tree model for the given namespace.
        /// </summary>
        /// <param name="id">Namespace id</param>
        public SiteTreeEditModel(Guid namespaceId)
        {
            // Get the namespaces
            using (var db = new DataContext()) {
                var ns = db.Namespaces.OrderBy(n => n.Name).ToList() ;
                if (namespaceId != Guid.Empty)
                    Namespaces = new SelectList(ns, "Id", "Name", namespaceId) ;
                Namespaces = new SelectList(ns, "Id", "Name") ;
            }

            // Get the available region types
            RegionTypes = new List<dynamic>() ;
            ExtensionManager.Extensions.Where(e => e.ExtensionType == ExtensionType.Region).OrderBy(e => e.Name).Each((i, r) =>
                RegionTypes.Add(new { Name = r.Name, Type = r.Type.ToString() })) ;
            RegionTypes.Insert(0, new { Name = "", Type = "" }) ;

            // Initialize the new site
            Id = Guid.NewGuid() ;
            NamespaceId = namespaceId ;
            Template = new PageTemplate() {
                Id = Id,
                Name = Id.ToString(),
                IsSiteTemplate = true
            } ;
            Regions = Template.RegionTemplates ;
        }

        public void TestContext(string context)
        {
            var ctx = new DataContext(context);

            ctx.GetTable<Person>().ToList();

            ctx.KeepConnectionAlive = true;

            ctx.GetTable<Person>().ToList();
            ctx.GetTable<Person>().ToList();

            ctx.KeepConnectionAlive = false;

            using (var tran = new DataContextTransaction(ctx))
            {
                ctx.GetTable<Person>().ToList();

                tran.BeginTransaction();

                ctx.GetTable<Person>().ToList();
                ctx.GetTable<Person>().ToList();

                tran.CommitTransaction();
            }
        }

        public CMetaobjectExtented(Guid ID, DataContext Context)
            : base(ID, Context)
        {
            this._likesNumberAttribute.Attributes = this._attributes;

            this.LikesNumber = 0;
        }

        public int AmountInsert(DataContext Context)
        {
            var Amounts = Context.GetTable<CMenuServiceOrderAmount>();
            Amounts.InsertOnSubmit(this);

            return CErrors.ERR_SUC;
        }

        public void Test2()
        {
            var dc = new DataContext();
            dc.AddTable("data", new[] {
                new Item { Col1="A", Col2 = 2 }
            });

            var flow = new Flow { Orientation = FlowOrientation.Vertical };
            var table = flow.AddTable<Item>("data");
            table.Columns.Single(a => a.DataField == "Col2").ConditionalFormatting = (value) => {
                if (!(value is int))
                    return null;
                var v = (int)value;
                if (v > 0)
                    return new Styling.CellStyle
                    {
                        FontStyle = new Styling.FontStyle
                        {
                            FontColor = Styling.Color.FromHtml("#00FF00")
                        }
                    };
                return null;
            };

            var rep = Report.CreateReport(flow, dc);
            var cells = ReportUtil.GetCellMatrix(rep);

            Assert.IsNull(cells[0][0].CustomStyle);
            Assert.IsNotNull(cells[0][1].CustomStyle);

            var html = HtmlReportWriter.RenderReport(rep, new DefaultHtmlReportTheme());
            Assert.IsTrue(html.Contains("style=\"color:"));
            Assert.IsTrue(html.Contains("#00FF00"));
        }

        public BlogsByUserViewModel(string username)
        {
            // Get back to the original name before url conversion
            BlogUsername = username.Replace(ContentGlobals.BLOGDELIMMETER, " ");

            using (var context = new DataContext())
            {

                // Get User based on authorid
                TheBlogUser = context.BlogUsers.FirstOrDefault(x => x.Username == BlogUsername);

                MaxBlogCount = BlogListModel.GetBlogSettings().MaxBlogsOnHomepageBeforeLoad;
                BlogTitle = BlogListModel.GetBlogSettings().BlogTitle;

                BlogsByUser = context.Blogs.Where(x => x.Author == BlogUsername && x.IsActive)
                            .OrderByDescending(blog => blog.Date)
                            .Take(MaxBlogCount)
                            .ToList();

                // Try permalink first
                TheBlog = BlogsByUser.FirstOrDefault(x => x.Author == BlogUsername);

                if (BlogsByUser.Count > 0)
                {
                    LastBlogId = BlogsByUser.LastOrDefault().BlogId;
                }
            }
        }

        public int LinkInsert(DataContext Context)
        {
            var Links = Context.GetTable<CRdsAttributeLink>();
            Links.InsertOnSubmit(this);

            return -1;
        }

        //cambBuscar
        //*creavuelo
        public Vuelo buscarporId(int idVuelo)
        {
            Vuelo vuelo = new Vuelo();
            MyConnection myConnection = new MyConnection();

            DataContext datacontext = new DataContext(myConnection.SQLConnection);

            var Table = datacontext.GetTable<Vuelo>();

            try
            {
                var buscarPorIdVuelo = from vueloId in Table
                                       where vueloId.IdVuelo == idVuelo
                                       select vueloId;
                foreach (Vuelo v in buscarPorIdVuelo)
                {
                    vuelo = v;
                }

            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }

            return vuelo;
        }