带有代码优先的EF 4.1中的TPH继承映射问题

我的ASP.NET MVC应用程序中包含以下类：

public abstract class Person {
    public int PersonId { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
}

public class Student : Person {
    public DateTime RegisteredOnUtc { get; set; }
    public int Age { get; set; }
}

public class Teacher : Person {
    public string LessonName { get; set; }
}

public class PersonMap : EntityTypeConfiguration<Person> {
    public PersonMap()
        : base() {

        this.HasKey(t => t.PersonId);

        this.Property(t => t.FirstName)
            .IsRequired()
            .HasMaxLength(50);

        this.Property(t => t.LastName)
            .IsRequired()
            .HasMaxLength(50);

        this.ToTable("Persons");

        this.Property(t => t.PersonId).HasColumnName("PersonId");
        this.Property(t => t.FirstName).HasColumnName("FirstName");
        this.Property(t => t.LastName).HasColumnName("LastName");

        this.Map<Student>(x => x.Requires("IsStudent").HasValue(true));
        this.Map<Teacher>(x => x.Requires("IsStudent").HasValue(false));
    }
}

public class StudentMap : EntityTypeConfiguration<Student> {
    public StudentMap()
        : base() {

        this.HasKey(t => t.PersonId); // Is this need or not???

        this.ToTable("Persons"); // Is this need or not???

        this.Property(t => t.RegisteredOnUtc).HasColumnName("RegisteredOn");
    }
}

public class TeacherMap : EntityTypeConfiguration<Teacher> {
    public TeacherMap()
        : base() {

        this.HasKey(t => t.PersonId); // Is this need or not???

        this.ToTable("Persons"); // Is this need or not???

        this.Property(t => t.LessonName)
            .IsRequired()
            .HasMaxLength(50);

        this.Property(t => t.LessonName).HasColumnName("Lesson");
    }
}

public class PersonContext : DbContext {

    public ObjectContext ObjectContext {
        get {
            return ((IObjectContextAdapter)this).ObjectContext;
        }
    }

    public DbSet<Person> Persons { get; set; }
    public DbSet<Student> Students { get; set; }
    public DbSet<Teacher> Teachers { get; set; }

    protected override void OnModelCreating(DbModelBuilder modelBuilder) {
        modelBuilder.Conventions.Remove<IncludeMetadataConvention>();
        modelBuilder.Configurations.Add(new PersonMap());
        modelBuilder.Configurations.Add(new StudentMap());
        modelBuilder.Configurations.Add(new TeacherMap());
    }

    public void Detach(object entity) {
        var objectContext = ((IObjectContextAdapter)this).ObjectContext;
        objectContext.Detach(entity);
    }
}

但是,当我运行该应用程序时,出现此错误：

属性“ PersonId”不是类型为“ Student”的已声明属性.通过使用Ignore方法或NotMappedAttribute数据批注,验证该属性未明确从模型中排除.确保它是有效的原始属性.

如果删除此代码,则为HasKey(t => t.PersonId);从学生和老师那里,将抛出此错误：

给定的键在词典中不存在.

您有什么想法要解决吗？谢谢.

解决方法:

您是否尝试从StudentMap和TeacherMap中删除这两行？

this.HasKey(t => t.PersonId); // Is this need or not???

this.ToTable("Persons"); // Is this need or not???

我复制了您的代码,并在没有这些行的情况下运行了它,效果很好.

标签：ef-code-first,mapping,entity-framework-4-1,c,entity-framework
来源： https://codeday.me/bug/20191207/2087549.html