EF 不允许启动新事务，因为有其他线程正在该会话中运行。

引起原因：在查询中提交了更改。如在遍历的时候，调用了savechanges（）；

解决：把savechange（）提到循环外.          

 

IOrderedQueryable<TOHOSPITAL_TBL> tb = ent.TOHOSPITAL_TBL.Where(record =>
                    (record.TOHOSPITAL_STATE_TYPE_TBL.VALUE == (int)ToHospitolState.treatment) ||
                    (record.TOHOSPITAL_STATE_TYPE_TBL.VALUE == (int)ToHospitolState.Clinic)).
                        OrderByDescending(record => record.TOHOSPITAL_TIME);
                foreach (TOHOSPITAL_TBL tohospotal in tb)
                {
                    if (!tohospotal.TOHOSPITAL_STATE_TYPE_TBLReference.IsLoaded)
                    {
                        tohospotal.TOHOSPITAL_STATE_TYPE_TBLReference.Load();
                    }
                    ChangeState(tohospotal);
               ent.SaveChanges();
                }
原因IOrderedQueryable<TOHOSPITAL_TBL> tb还在查询中，调用ent.SaveChanges();产生的。

ent.SaveChanges();提出即可

代码：

                IOrderedQueryable<TOHOSPITAL_TBL> tb = ent.TOHOSPITAL_TBL.Where(record =>
                    (record.TOHOSPITAL_STATE_TYPE_TBL.VALUE == (int)ToHospitolState.treatment) ||
                    (record.TOHOSPITAL_STATE_TYPE_TBL.VALUE == (int)ToHospitolState.Clinic)).
                        OrderByDescending(record => record.TOHOSPITAL_TIME);
                foreach (TOHOSPITAL_TBL tohospotal in tb)
                {
                    if (!tohospotal.TOHOSPITAL_STATE_TYPE_TBLReference.IsLoaded)
                    {
                        tohospotal.TOHOSPITAL_STATE_TYPE_TBLReference.Load();
                    }
                    ChangeState(tohospotal);
                }
                ent.SaveChanges();