播种不适用于 EF 4.1

Question

我在 ASP.NET MVC 教程的帮助下创建了以下代码。 它们位于我称为 Model 的不同类库中。 我在类库中创建了一个 app.config，其中包含名为 HRContext 的连接字符串。 另外，在网络项目上我创建了相同的连接字符串。

当我运行该项目时，我设置了断点，并且 Seed 方法从未执行，但 OnModelCreating 正在执行。

我收到一个异常，说视图中不存在表 dbo.Position。

Exception Details: System.Data.SqlClient.SqlException: Invalid object name 'dbo.Position'.



Line 21:             var positions = unitOfWork.PositionRepository.Find(p => p.PositionID != null);
Line 22: 
Line 23:             return View(positions.ToList());
Line 24:         }








 public class HRContextInitializer : DropCreateDatabaseAlways<HRContext>
    {
        protected override void Seed(HRContext context)
        {
            Position netdeveloper = new Position() { name = ".net developer", yearsExperienceRequired = 5 };
            Position javadeveloper = new Position() { name = "java developer", yearsExperienceRequired = 5 };

            byte[] johnImage = File.ReadAllBytes(@"\Content\Photos\1.jpg");
            byte[] luisImage = File.ReadAllBytes(@"\Content\Photos\2.jpg");

            Applicant luis = new Applicant()
            {
                name = "Luis",
                skypeuser = "le.valencia",
                telephone = "0491732825",
                photo = luisImage
            };

            Applicant john = new Applicant()
            {
                name = "John",
                skypeuser = "jo.valencia",
                telephone = "3435343543",
                photo = johnImage
            };


            ApplicantPosition appicantposition = new ApplicantPosition()
            {
                Applicant = luis,
                Position = netdeveloper,
                appliedDate = DateTime.Today,
                Status = Status.Applied
            };

            ApplicantPosition appicantposition2 = new ApplicantPosition()
            {
                Applicant = john,
                Position = javadeveloper,
                appliedDate = DateTime.Today,
                Status = Status.Applied
            };

            context.Positions.Add(netdeveloper);
            context.Positions.Add(javadeveloper);
            context.Applicants.Add(luis);
            context.Applicants.Add(john);
            context.ApplicantsPositions.Add(appicantposition);

            context.SaveChanges();
        }
    }




public class HRContext : DbContext
    {
        public DbSet<Position> Positions { get; set; }
        public DbSet<Applicant> Applicants { get; set; }
        public DbSet<ApplicantPosition> ApplicantsPositions { get; set; }
        public DbSet<ApplicationPositionHistory> ApplicationsPositionHistory { get; set; }

        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            modelBuilder.Entity<Position>().ToTable("Position");
            modelBuilder.Entity<Applicant>().ToTable("Applicant");
            modelBuilder.Entity<ApplicantPosition>().ToTable("ApplicantPosition");
            modelBuilder.Entity<ApplicationPositionHistory>().ToTable("ApplicationsPositionHistory");

            modelBuilder.Entity<Position>().Property(c => c.name).IsRequired();
            modelBuilder.Entity<Applicant>().Property(c => c.name).IsRequired();
            modelBuilder.Entity<ApplicantPosition>().Property(c => c.appliedDate).IsRequired();

            base.OnModelCreating(modelBuilder);
        }
    }

Answer 1

您需要告诉 EF 使用自定义初始化程序 Database.SetInitializer 方法。最好在应用程序启动时调用它（如果您使用 MVC，则在 Application_Start 中）。但你应该只在第一次访问上下文之前调用它一次

protected void Application_Start()
{
     ...
    Database.SetInitializer(new HRContextInitializer());
     ...
}

Answer 2

在您的 HRContext 类中，您需要设置数据库初始值设定项：

protected override void OnModelCreating(DbModelBuilder modelBuilder) 
{ 
    Database.SetInitializer(new HTContextInitializer());
}