从一个对象到同一实体类型的两个对象的多个关联
我尝试首先使用代码和流畅的 API 创建一个对象，该对象包含同一个表中的两个不同实体。换句话说，传输对象保存对两个不同坦克对象的引用——一个是源，另一个是目的地。
但是，当我使用以下代码时，我收到一个异常，指出“引用关系将导致不允许的循环引用”。
modelBuilder.Entity<Transfer>()
.HasRequired<Tank>(t => t.Source)
.WithMany(t => t.OutboundTransfers);
modelBuilder.Entity<Transfer>()
.HasRequired<Tank>(t => t.Destination)
.WithMany(t => t.InboundTransfers);
我最好的猜测是它认为我将两把钥匙都指向同一个坦克？知道我怎样才能做到这一点吗？
编辑：找到答案，从 实体框架代码优先 - 来自同一个表的两个外键
I am attempting to use code first and the fluent API to create an object that holds two different entities from the same table. In other words, a transfer object holds a reference to two different tank objects--one is the source and the other the destination.
However, when I use the following code I get an Exception stating that "The referential relationship will result in a cyclical reference that is not allowed."
modelBuilder.Entity<Transfer>()
.HasRequired<Tank>(t => t.Source)
.WithMany(t => t.OutboundTransfers);
modelBuilder.Entity<Transfer>()
.HasRequired<Tank>(t => t.Destination)
.WithMany(t => t.InboundTransfers);
My best guess is that it thinks I am pointing both keys to the same Tank? Any idea how I can accomplish this?
EDIT: Found the answer as adding .WillCascadeOnDelete(false) from Entity Framework Code First - two Foreign Keys from same table
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正如您所说，您应该能够添加
.WillCascadeOnDelete(false)- https://stackoverflow.com /a/5559300/5416我刚刚添加了此答案，以便它不再显示在未答复列表中，因为未答复的答案为零。标记为社区 wiki :)
As you stated, you should be able to add
.WillCascadeOnDelete(false)- https://stackoverflow.com/a/5559300/5416I just added this answer so that it doesn't show on the unanswered list any more as unanswered with zero answers. Marked as community wiki :)
像往常一样，Ladislav（EF 大师）有 EF 问题的答案。 （感谢拉迪斯拉夫）
只是我发现有用的替代方案。
我有并行运行的第二个解决方案。
如果我每个人都有代码优先问题。我首先尝试一下：
逆向工程师对第一个解决方案进行编码。（来自 EF 电动工具）
我有一个测试数据库，我在数据库中手动添加所需的概念。
我仍然发现在数据库中执行此操作更直观，因为我首先是代码新手。
然后使用电动工具
http://visualstudiogallery.msdn.microsoft.com/72a60b14-1581-4b9b -89f2-846072eff19d
在项目/解决方案上右键单击实体框架，首先对数据库进行逆向工程以进行代码。
查看它生成的代码。你会得到一个如何做某事的例子。
As usual Ladislav (EF Guru) has the answer to EF questions. (thanks Ladislav)
Just an alternate i have found useful.
I have an second solution I run in parallel.
If I every have a code first issue. I first try thi:
The reverse engineer to code first solution.(from EF power tools)
I have a test DB where I add the required concept by hand in a DB.
I still find doing this in the DB more intuitive as im new to code first.
Then using the powertool
http://visualstudiogallery.msdn.microsoft.com/72a60b14-1581-4b9b-89f2-846072eff19d
on the Project/Solution right click Entity framework, reverse engineer DB to code first.
Check out the code it generartes. you get an example of how to do somethings.