如何在Entity Framework 4.0中使用插入事件将字段添加到相关表？ [英] How do I use Inserting Event in Entity Framework 4.0 to add fields to a related table?
问题描述
Supose我有2张桌子b
usersTable
• userid guid not null
•用户名nvarchar
• ...更多字段
OrderTable
• Orderid int not null
• OrderTitle nvarchar
• userid guid not null //这是一个FK
• username nvarchar not null
• ...更多字段
要添加订单，用户必须因此我这样做是为了获得他们的userId和用户名
'让用户当前登录。然后我可以将其绑定到文本框等。
       Dim currentUser As MembershipUser = Membership.GetUser（）
'确定当前登录用户的UserId值
Dim currentUserId As Guid = CType（currentUser.ProviderUserKey，Guid）
我想要的是，当一个 订单插入 ordertable 时登录用户，我想将用户名和用户ID添加到
ordertable。我正在使用Entity FrameWork 4.0，一个DetailsView 并在VB + VS2010中编程。 />
谢谢你
Supose I have 2 tables
usersTable
•userid guid not null
•username nvarchar
•...more fields
OrderTable
•Orderid int not null
•OrderTitle nvarchar
•userid guid not null //This is a FK
•username nvarchar not null
•...more fields
To add an order, a user has to be loged in. So I do this to get their userId and username
' get the user currently logged in. I can then bound it to Textbox etc
Dim currentUser As MembershipUser = Membership.GetUser()
' Determine the currently logged on user's UserId value
Dim currentUserId As Guid = CType(currentUser.ProviderUserKey, Guid)
What I want is, when an Order is inserted into the ordertable by the logged in user, I want to add the username and userid to the
ordertable. I am using Entity FrameWork 4.0, a DetailsView and programming in VB + VS2010.
thanks yousaid
推荐答案
你好，
我们可以定义自己的业务逻辑来添加插入的Order实体的一些值。  
一般来说，我们在这里列出的业务逻辑中有几个要处理的事件，
http://msdn.microsoft.com/en-us/library/dd456876.aspx 。
We can define our own business logic to add some values of the inserted Order entities. Generally, we have several events to handle in our business logic which are listed here, http://msdn.microsoft.com/en-us/library/dd456876.aspx.
我建议处理SavingChanges事件处理程序并使用ObjectStateManager.GetObjectStateEntries（EntityState.Added）来获取所有已添加
状态的实体。  对于这些添加的条目，我们可以继续检索所有插入的订单实体并设置其userId和用户名属性。
详情请参阅 http://msdn.microsoft.com/en-us/library/cc716714.aspx 。  
I would recommend handle the SavingChanges event handler and use ObjectStateManager.GetObjectStateEntries(EntityState.Added) to get all the entities which are in Added status. For these added entries, we can go on to retrieve all the inserted Order entities and set their userId and username properties. For detail, please see http://msdn.microsoft.com/en-us/library/cc716714.aspx.
如果您有任何疑问，请随时告诉我。
美好的一天！
最诚挚的问候，
Lingzhi Sun
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