Question

我有下面的Post Action方法，它将两个参数传递给存储库方法： -

 [HttpPost]
        public void Delete(string id, int classid )
        {
            repository.Deleteuserclass(id, classid);        }

存储库方法是： -

public void Deleteuserclass(string a, int u)

    {
        entities.deleteuserclass(a,u);}

最后，存储库方法将调用以下存储过程： -

ALTER PROCEDURE dbo.deleteuserclass
@userid nvarchar(50),
@classid int
AS
Begin

Delete from Users_Classes where UserID = @userid  AND ClassID = @classid
END

如何将异常传递给将在数据库端引发的操作方法，因为存储过程没有删除任何记录？

修改： - 我更新存储过程如下： -

ALTER PROCEDURE dbo.deleteuserclass
@userid nvarchar(50),
@classid int
AS
Begin

Delete from Users_Classes where UserID = @userid  AND ClassID = @classid
if @@rowcount = 0     
    Raiserror('No record deleted',1,16) 
END

我更新了动作方法： -

        public ActionResult Delete(string id, int classid ) {
try{
                       Thread.Sleep(1000);
                       Users_Classes u_c = r.FindUserClass(id, classid);
                       r.Deleteuserclass(id, classid);
                       return Json(new { IsSuccess = "True", id = u_c.UserID + u_c.AddedDate.ToString("ddMMyyyyHHmmss"), name = u_c.UserID }, JsonRequestBehavior.AllowGet);
                   }
                   catch (ArgumentNullException)
                   {
                       return Json(new { IsSuccess = "F1" }, JsonRequestBehavior.AllowGet);}
                   catch (DbUpdateConcurrencyException)
                   {return Json(new { IsSuccess = "F2" }, JsonRequestBehavior.AllowGet); }
                   catch (NullReferenceException)
                   {return Json(new { IsSuccess = "F4" }, JsonRequestBehavior.AllowGet); }
                   catch (Exception e)
                   {return Json(new { IsSuccess = "F5" }, JsonRequestBehavior.AllowGet);}

但问题是如果存储过程没有删除任何记录，那么应用程序将在NullReferenceException上引发后续异常return Json(new { IsSuccess = "True", id = u_c.UserID + u_c.AddedDate.ToString("ddMMyyyyHHmmss"), name = u_c.UserID }, JsonRequestBehavior.AllowGet);，并且它不会引发应该已经引发的异常在存储过程级别'No record deleted'上，在达到return声明之前.. 那么可能是什么问题？

Answer 1

您要做的是从存储过程中传递不规则的返回值。您可以修改存储过程，如下所示：

ALTER PROCEDURE dbo.deleteuserclass
@userid nvarchar(50),
@classid int
AS
Begin

Delete from Users_Classes 
where UserID = @userid  
AND ClassID = @classid

if @@rowcount = 0
    return -1

END

我不确定你是如何调用存储过程的（不熟悉EF），但你应该能够捕获一个返回值：

// notice this method now returns bool instead of void
public bool Deleteuserclass(string a, int u)
{
    return entities.deleteuserclass(a,u) > 0;
}

然后在您的POST操作方法中，只测试bool方法的DeleteUserClass()结果：

[HttpPost]
public void Delete(string id, int classid )
{
    if (!repository.Deleteuserclass(id, classid))
        // no user deleted, handle accordingly        
}

Answer 2

将存储过程修改为

ALTER PROCEDURE dbo.deleteuserclass 
  @userid nvarchar(50), 
  @classid int 
AS 
Begin  
  Delete from Users_Classes  where UserID = @userid   AND ClassID = @classid  

  if @@rowcount = 0     
    Raiserror('User Deletion failed',1,16)
END

处理异常并重新抛出存储库方法

public void Deleteuserclass(string a, int u)      
{
  try{
         entities.deleteuserclass(a,u);
  }catch(Exception e)
  {
    throw e;
  }
}

最后，将调用方法修改为

public bool Deleteuserclass(string a, int u) 
{
    try{
     return entities.deleteuserclass(a,u) > 0; 
    }
    catch(Exception e)
    {
      //handle exception
      logError(e.Message);
    }
}

如何将异常从存储过程传递到Post Action方法

2 个答案: