数据上下文的SubmitChanges方法导致实体引用设置为null

MotherClass看起来像这样:

public class MotherClass
{
     private EntitySet<ChildClass> _Children;

     [Column]
     public int Id { get; set; }

     [Association(Storage = "_Children", ThisKey = "Id", OtherKey = "MotherId")]
     public EntitySet<ChildClass> Children
     {
           get { return _Children; }
           set { _Children= value; }
     }
}

ChildClass看起来像:

public class ChildClass
{
     private EntityRef<MotherClass> _Mother;
     private EntitySet<ChildChildrenClass> _ChildChildren;

     [Column]
     public int Id { get; set; }

     [Column]
     public int MotherId { get; set; }

     [Association(Storage = "_Mother", IsForeignKey = true, ThisKey = "MotherId", OtherKey = "Id")]
     public MotherClass Mother
     {
           get { return _Mother.Entity; }
           set { _Mother.Entity = value; }
     }

     [Association(Storage = "_ChildChildren", ThisKey = "Id", OtherKey = "ChildId", DeleteRule = "NO ACTION")]
     public EntitySet<ChildChildrenClass> ChildChildren
     {
           get { return _ChildChildren; }
           set { _ChildChildren= value; }
     }
}

第三种职业被神奇地命名为childrenclass:

public class ChildChildrenClass
    {
         private EntityRef<ChildClass> _Child;

         [Column]
         public int Id { get; set; }

         [Column]
         public int ChildId { get; set; }

         [Association(Storage = "_Child", IsForeignKey = true, ThisKey = "ChildId", OtherKey = "Id")]
         public ChildClass Child
         {
               get { return _Child.Entity; }
               set { _Child.Entity = value; }
         }
    }

当我们对ChildClass对象进行更新并删除与之关联的一些childrenClass项时,问题就出现了是的。是的代码如下所示:

DataContext dc = new DataContext(conStr);
dc.StartTransaction();//our custom method for handling transactions
ChildClass cclass = dc.ChildClass.GetById(id);//our method for getting the ChildClass from db
//... here we set some values we want to edit
//...
//...
dc.SubmitChanges(ConflictMode.FailOnFirstConflict);//these actions are cool
//after this the problems arise
 List<ChildChildrenClass> ccc = GetAllChildren();//method that gets all the childChildrenClass objects from db
foreach (ChildChildrenClass child in ccc)
{
     dc.GetTable(child.GetType()).DeleteOnSubmit(child);
}
dc.SubmitChanges(ConflictMode.FailOnFirstConflict);
//AFTER CALLING THIS METHOD THE PROBLEM APPEARS

上面提到的问题是班级。妈妈属性被神奇地设置为null。经过大量调试(在母集方法中放置brakepoints揭示了这一点),我们注意到在一些外部代码中SubmitChanges()期间,属性被设置为null。

SubmitChanges()方法成功完成(将删除childrenClass项),但这会导致在此之后运行的代码出现问题。我们正在使用相同的DataContext(因为事务),并再次调用引发此异常的SubmitChanges()方法:

在系统数据.Linq.ChangeTracker.StandardChangeTrackerS标准跟踪对象.SynchDependentData() 在系统数据.Linq.ChangeProcessor.SubmitChanges文件(冲突模式故障模式)