System.InvalidOperationException:This.NpgsqlTransaction has completed;it is no longer usable. at Npgsql.NpgsqlTransaction.CheckCompleted() in ...

　About this exception report, because the transaction can not be recycled submitted, the transaction can only be submitted once a method.

System.InvalidOperationException:This.NpgsqlTransaction has completed;it is no longer usable. at Npgsql.NpgsqlTransaction.CheckCompleted() in ...

  Proper use

 the using ( var Pay = _postgreDbContext.Database.BeginTransaction ()) 
            { 
                the try 
                { 
                    billItem.review_remark = " through " ;
                     the foreach ( var Item in Settlement) 
                    { 
                        item.status = 2 ; 
                    } 
                    _postgreDbContext.SaveChanges ();   pay.Commit () ; // Note placed outside the loop 
                } 
                  

                the catch (Exception EX) 
                { 
                    the throw ex;
                }
            }