EF代码优先一对一关系级联删除错误

Question

我定义了以下类。当我调用DeleteProperty方法时，它给我一个错误。不知道我在想什么..

我正在使用EF代码优先方法来创建数据库中所需的架构。

数据库架构看起来不错。它创建了属性表和属性地址表，并且属性地址表以propertyId作为外键。当我通过UI添加属性对象时，属性记录已添加确定。但是，当我尝试从UI删除Property对象时，出现以下错误。

   A relationship from the 'Property_PropertyAddress' AssociationSet is in the 'Deleted' state. Given multiplicity constraints, a corresponding 'Property_PropertyAddress_Target' must also in the 'Deleted' state.

任何帮助将不胜感激。

    // base class
            public  abstract class BaseEntity
            {
                public int ID { get; set; }
                public DateTime CreatedDate { get; set; }
                public DateTime ModifiedDate { get; set; }      
            }

// property class
            public class Property : BaseEntity
            {        
                // one to one relation with Property address
                public virtual PropertyAddress PropertyAddress { get; set; }            
                // other properties....            
            }

            public class PropertyMap : EntityTypeConfiguration<Property>
            {
                public PropertyMap()
                {
                    // key
                    HasKey(t => t.ID);

                    // fields           
                    Property(t => t.ID).HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);            

                    Property(t => t.CreatedDate).IsRequired();
                    Property(t => t.ModifiedDate).IsRequired();

                    // other

                    // table name
                    ToTable("Property");            

                }
            }

            public class PropertyAddress :BaseEntity
            {              
                public virtual Property Property { get; set; }

                // other properties.....
            }

 public class PropertyAddressMap: EntityTypeConfiguration<PropertyAddress>
 {
                public PropertyAddressMap()
                {
                    // key
                    HasKey(t => t.ID);

                    // fields
                    Property(t => t.ID).HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);           

                    Property(t => t.CreatedDate).IsRequired();
                    Property(t => t.ModifiedDate).IsRequired();

                    // table name
                    ToTable("PropertyAddress");         

          HasRequired(t=>t.Property).WithRequiredDependent(p=>p.PropertyAddress).Map(m => m.MapKey("PropertyId")).WillCascadeOnDelete(true);
                }
            }




        public int DeleteProperty(int id)
                {
                    // get the property by id and then delete.
                    var property = GetProperty(id);
                    return repository.Delete(property);
                }


        Delete method in repository class:

        public virtual int Delete<T>(T entity) where T : BaseEntity
                {

                    // check for null argument
                    ThrowArgumentNullException(entity);
                    try
                    {
                        context.Set<T>().Remove(entity);
                        return context.SaveChanges();
                    }
                    catch (Exception ex)
                    {
                        throw new Exception(ex.Message);                
                    }

                }