Question

I m having a problem that I thought was easy to resolve. This is my scenario (Entity framework 4 disconnected entities using self tracking). Let s say I have 2 entities: Users, Orders. From an asp.net page a get from the database 1 user and 1 order.

const int userId = 1;
const int orderId = 1;
var userManager = new UserManager();
var orderManager = new OrderManager();
var user = userManager.GetUser(userId);
var order = channelManager.GetChannel(channelId);

user.Orders.Add(order);

现在,我需要建立一种功能,更新用户的订单。

我写道:

public bool UpdateUser(User user)
{
    context.AttachTo("Users", user);

    var stateMgr = context.ObjectStateManager;
    var stateEntry = stateMgr.GetObjectStateEntry(user);

    for (int i = 0; i < stateEntry.CurrentValues.FieldCount; i++)
    {
            bool isKey = false;

            string name = stateEntry.CurrentValues.GetName(i);

            foreach (var keyPair in stateEntry.EntityKey.EntityKeyValues)
            {
                    if (string.Compare(name, keyPair.Key, true) == 0)
                    {
                            isKey = true;
                            break;
                    }
            }
            if (!isKey)
            {
                    stateEntry.SetModifiedProperty(name);
            }
    } 

    context.ApplyCurrentValues("Users", user);

    return context.SaveChanges() > 0;
}

I don t have any error on this function and debugging everything seems to be ok, but when I check on the database the entity is not updated as expected. I thought update a disconnected entity was something simple but apparently is not. Can someone explaing me the logic between the update the entire graph of disconnected object with EF4? Please if you can I need to undestand the logic and not have a collection of links to look at. I already spent some time looking on internet but I m finding so many approches that I m not sure which one is correct.

增编

Answer 1

我看不出与自我跟踪实体有任何关系。任何与ASP.NET连接的STEs: t 工作非常好。

你们的法典应当做些什么? 请你这样做:

public bool UpdateUser(User user)
{
    context.AttachTo("Users", user);
    context.ObjectStateManager.ChangeObjectState(user, EntityState.Modified);
    return context.SaveChanges() > 0;
}

但网站将不节省。我仅回答了有关

Answer 2

自我跟踪贵实体必须使用“ApplyChanges()”方法,在情况上对变化进行总结(而不是附上)。

申请表将转至图表,以更新相关物体/收集。

 Public Function UpdateEntity(entity As Entity) As Entity

    Using dbContext As New EntityContext()
        dbContext.EntitySet.ApplyChanges(entity)
        dbContext.SaveChanges()

        dbContext.Refresh(Objects.RefreshMode.StoreWins, entity)
    End Using

    Return entity 
End Function

复读是选择性的,在这里只能推回数据库的最后价值。复读方式没有更新相关物体。

友情链接