Exemplo n.º 1
0
        public IQueryable <T> LoadEntities <T, OrderType>(EFPager <T, OrderType> pager) where T : class
        {
            if (pager.PageSize < 1)
            {
                pager.PageSize = 1;
            }
            if (pager.PageIndex < 0)
            {
                pager.PageIndex = 0;
            }

            IQueryable <T> query     = db.Set <T>().Where <T>(pager.WhereLambds);
            int            rowsCount = query.Count();

            pager.SetTotalCount(rowsCount);
            int pagesCount = rowsCount % pager.PageSize == 0 ? (rowsCount / pager.PageSize) : (rowsCount / pager.PageSize + 1);

            pager.SetTotalPages(pagesCount);
            if (pager.PageIndex >= pagesCount)
            {
                pager.PageIndex = (pagesCount <= 0?0: pagesCount - 1);
            }

            if (pager.IsAsc)
            {
                query = query.OrderBy <T, OrderType>(pager.OrderByLambds);
            }
            else
            {
                query = query.OrderByDescending <T, OrderType>(pager.OrderByLambds);
            }

            query = query.Skip <T>(pager.PageSize * pager.PageIndex).Take <T>(pager.PageSize);


            return(query);
        }
Exemplo n.º 2
0
        /// <summary>
        /// 获取列表数据
        /// </summary>
        /// <param name="pageIndex"></param>
        /// <param name="pageSize"></param>
        /// <returns></returns>
        public UIPager GetDataList(int pageIndex, int pageSize)
        {
            UIPager uip = new UIPager();

            EFPager <ChatHistories, DateTime> pager = new EFPager <ChatHistories, DateTime>();

            pager.PageIndex = pageIndex;
            pager.PageSize  = pageSize;
            //pager.WhereLambds = x => DbFunctions.DiffDays(x.CreateTime, DateTime.Now) == 0;
            pager.WhereLambds   = x => 1 == 1;
            pager.IsAsc         = false;
            pager.OrderByLambds = o => o.CreateTime;

            IQueryable <ChatHistories> items = LoadEntities <ChatHistories, DateTime>(pager);

            uip.PageSize   = pager.PageSize;
            uip.PageIndex  = pager.PageIndex;
            uip.TotalCount = pager.TotalCount;
            uip.TotalPages = pager.TotalPages;

            List <ChatHistoryView> list = new List <ChatHistoryView>();

            foreach (var it in items)
            {
                ChatHistoryView view = new ChatHistoryView();
                view.ChatContent = Utils.ReplaceIllegalWord(it.ChatContent);
                view.CreateTime  = it.CreateTime.ToString("yyyy-MM-dd HH:mm:ss");
                view.ClientName  = it.ClientName;
                view.IdentityMd5 = it.IdentityMd5;
                view.ImgIndex    = it.ImgIndex;
                list.Add(view);
            }

            uip.ReponseObj = list.OrderBy(x => x.CreateTime).ToList();
            return(uip);
        }
Exemplo n.º 3
0
        /// <summary>
        /// All tests/work are performed here
        /// </summary>
        /// <returns></returns>
        internal async Task DoWork()
        {
            // Create DSuite dummy data to play with
            await PopulateDummyCars(500);

            // Demonstrate the deferred execution POWER of IQueryable!
            // Find a small list of cars that we don't need to page through.
            FindMultipleUsingHelperClass(_dSuite);

            //------- Same query using pure LINQ -----------------
            FindMultipleUsingLINQ();

            // Ask the DBContextFactory to create the desired DbContext object for use for database access
            await CRUDUsingHelperClass();

            // Equivalent CRUD using just linq
            await CRUDUsingLINQ();


            // Demonstrate data PAGING! Construct a pager that specifies the where clause, page size and column order criteria
            EFPager <Car> pager = new EFPager <Car>(x => x.Mileage > 50000, 50, x => x.Make, x => x.Model, x => x.Mileage);

            do
            {
                // Note: The database will NOT be accessed during this call.
                IQueryable <Car> resultQuery = await EFHelper.QueryEntities <Car, DSuiteContext>(pager);

                // Physically realize the data from the database. The act of enumeration causes the current thread
                // to block while data is retrieved from the database. To perform this asynchronously, use the RealizeData extension.
                resultQuery.DumpData($"\r\n\r\n==============Page {pager.PageIndex} of Car data==============================");
            } while (pager.HasNextPage);
            Console.WriteLine($"Query {pager}:: {pager.TotalRowCount} total rows in {pager.TotalPages} pages were displayed\r\n\r\n");


            // Delete all play data
            EFCrud.DeleteAll <Car, DSuiteContext>();

            //-------------------- Use Code First ----------------------
            // Ask the DBContextFactory to create the desired DbContext object for use for database access.
            // NOTE: This is for demo purposes only! The DbContexts for this application were injected
            //       in the constructor, and this is how you would "USUALLY" access the DbContext to work with.
            SchoolContext schoolContext = DBContextFactory.GetDbContext <SchoolContext>();

            DbInitializer.Initialize(schoolContext);

            IQueryable <Student> studentList = schoolContext.FindMultiple <Student, SchoolContext>((x) => x.LastName.StartsWith("A"), (x) => x.LastName, false);

            studentList.DumpData($"\r\n\r\n==============EFCrud.FindMultiple==============================");

            // Demonstrate basic CRUD with related tables
            Student newStudent = new Student {
                FirstMidName = "Tony", LastName = "Franklin", EnrollmentDate = DateTime.Parse("2009-09-09")
            };
            await schoolContext.Create(newStudent);

            Course newCourse = new Course {
                CourseID = 5022, Title = "Advanced C#", Credits = 4
            };
            await schoolContext.Create(newCourse);

            Enrollment newEnrollment = new Enrollment {
                StudentID = newStudent.Id, CourseID = newCourse.CourseID, Grade = Grade.A
            };
            await schoolContext.Create(newEnrollment);

            // Now find a specific enrollment.
            Enrollment enrollmentFound = schoolContext.FindSingle <Enrollment, SchoolContext>(x => x.EnrollmentID == newEnrollment.EnrollmentID);
            string     grade           = enrollmentFound?.Grade.ToString() ?? "??";

            Console.WriteLine($"Student({enrollmentFound.Student.FirstMidName} {enrollmentFound.Student.LastName}) Course({enrollmentFound.Course.Title}) Grade({grade})");

            // Delete the student that was just added
            schoolContext.Delete(newEnrollment);
            schoolContext.Delete(newCourse);
            schoolContext.Delete(newStudent);

            // Find all classes a student is enrolled into. NOTE:!!!! DbContextFactory uses "UseLazyLoadingProxies"
            // to ensure that properties "Student" and "Course" are lazy loaded when their properties are accessed.
            // If that were not the case, then you've have to manually load the data based on ID values.
            newStudent = schoolContext.FindSingle <Student, SchoolContext>(x => x.LastName == "Alonso" && x.FirstMidName == "Meredith");
            IQueryable <Enrollment> enrolledList = schoolContext.FindMultiple <Enrollment, SchoolContext>(x => x.StudentID == newStudent.Id);

            Console.WriteLine("\r\nMeredith Alonso was inrolled in the following courses:");
            foreach (Enrollment enrolled in enrolledList.ToList())
            {
                Console.WriteLine($"{enrolled.Course.Title} enrolled on {enrolled.Student.EnrollmentDate}");
            }

            // Use the DbContext classes that were passed in using Dependency Injection
            Car myCar = GenerateCar();

            _dSuite.Cars.Add(myCar);
            _dSuite.SaveChanges();
            myCar.TraceInformation("Using DI created context");
            Car foundMyCar = (from c in _dSuite.Cars where c.CarId == myCar.CarId select c).FirstOrDefault();

            foundMyCar.TraceInformation("Example of how to use LINQ to find an entity");

            // Use generic repository pattern (using dependency injection)
            foundMyCar = _cars.GetById(myCar.CarId);
            foundMyCar.TraceInformation("Found using generic repository");

            // Remove the car to clean up the DB
            _dSuite.Cars.Remove(myCar);
            _dSuite.SaveChanges();

            // Use the open generic type provided by dependency injection for the "school" repo
            Student Bobby = new Student {
                FirstMidName = "Bobby", LastName = "Simpson", EnrollmentDate = DateTime.Parse("2010-08-01")
            };

            _genericStudentDataRepository.Insert(Bobby);
            Bobby.TraceInformation("New student inserted using dependency injection open generic");
            Student foundStudent = _genericStudentDataRepository.GetById(Bobby.Id);

            foundStudent.TraceInformation("Found student using dependency injection open generic");
            _genericStudentDataRepository.Delete(Bobby.Id);
            foundStudent = _genericStudentDataRepository.GetById(Bobby.Id);
            if (foundStudent == null)
            {
                Bobby.TraceInformation("Successfully deleted student");
            }
            else
            {
                Bobby.TraceInformation("Failed to deleted student");
            }

            // Perform the same action with the IStudentRepository
            Bobby = new Student {
                FirstMidName = "Bobby", LastName = "Simpson", EnrollmentDate = DateTime.Parse("2010-08-01")
            };
            _students.Insert(Bobby);
            Bobby.TraceInformation("New student inserted using dependency injection open generic");
            foundStudent = _students.GetById(Bobby.Id);
            foundStudent.TraceInformation("Found student using dependency injection open generic");
            _students.Delete(Bobby.Id);
            foundStudent = _students.GetById(Bobby.Id);
            if (foundStudent == null)
            {
                Bobby.TraceInformation("Successfully deleted student");
            }
            else
            {
                Bobby.TraceInformation("Failed to deleted student");
            }
        }
Exemplo n.º 4
0
 public IQueryable <T> LoadEntities <T, OrderType>(EFPager <T, OrderType> pager) where T : class
 {
     return(dao.LoadEntities(pager));
 }