避免在实体框架代码优先的循环依赖

假设我有两个实体：国籍和雇员,关系为1：n.

public class Employee
{
    public int Id { get; set; }
    // More Properties

    public virtual Nationality Nationality { get; set; }
}

public class Nationality
{
    public int Id { get; set; }
    public string Name { get; set; }
}

为了将Code-First与Entity Framework结合使用,我必须再添加一个属性：不希望进入国籍的员工(它会产生循环依赖)：

public class Nationality
{
    public int Id { get; set; }
    public string Name { get; set; }

    // How to avoid this property
    public virtual List<Employee> Employees { get; set; }
}

这样我就可以在Configuration类中配置关系1：n：

internal class EmployeeConfiguration : EntityTypeConfiguration<Employee>
{
    public EmployeeConfiguration()
    {
        HasKey(f => f.Id);

        HasRequired(e => e.Nationality)
          .WithMany(e => e.Employees)
          .Map(c => c.MapKey("NationalityId"));

        ToTable("Employees");
    }
}

还有其他方法可以避免循环依赖并消除不属于国籍类别的员工吗？

解决方法:

使用WithMany()重载来配置映射.

internal class EmployeeConfiguration : EntityTypeConfiguration<Employee>
{
    public EmployeeConfiguration()
    {
        HasKey(f => f.Id);

        HasRequired(e => e.Nationality)
          .WithMany()
          .Map(c => c.MapKey("NationalityId"));

        ToTable("Employees");
    }
}

标签：ef-code-first,entity-framework-5,c,entity-framework
来源： https://codeday.me/bug/20191031/1975317.html