StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

PO
primarykey
Id
10194299
data
AcceptedAnswerId
0
AnswerCount
0
ClosedDate
CommentCount
5
CommunityOwnedDate
CreationDate
2012-04-17T15:35:29.510
FavoriteCount
0
LastActivityDate
2012-04-17T15:35:29.510
LastEditDate
LastEditorUserId
0
OwnerUserId
270591
ParentId
10191734
PostTypeId
2
Score
218
ViewCount
0
LastEditorDisplayName
text
Body
Because these two lines ... <pre><code>EmployeeService es = new EmployeeService(); CityService cs = new CityService(); </code></pre> ... don't take a parameter in the constructor, I guess that you create a context within the classes. When you load the <code>city1</code>... <pre><code>Payroll.Entities.City city1 = cs.SelectCity(...); </code></pre> ...you attach the <code>city1</code> to the context in <code>CityService</code>. Later you add a <code>city1</code> as a reference to the new <code>Employee</code> <code>e1</code> and add <code>e1</code> including this reference to <code>city1</code> to the context in <code>EmployeeService</code>. As a result you have <code>city1</code> attached to two different context which is what the exception complains about. You can fix this by creating a context outside of the service classes and injecting and using it in both services: <pre><code>EmployeeService es = new EmployeeService(context); CityService cs = new CityService(context); // same context instance </code></pre> Your service classes look a bit like repositories which are responsible for only a single entity type. In such a case you will always have trouble as soon as relationships between entities are involved when you use separate contexts for the services. You can also create a single service which is responsible for a set of closely related entities, like an <code>EmployeeCityService</code> (which has a single context) and delegate the whole operation in your <code>Button1_Click</code> method to a method of this service.
Tags
Title
singulars
PostAcceptedAnswerId
1. This table or related slice is empty.
PostParentId
1. POentity object cannot be referenced by multiple instances of IEntityChangeTracker. while adding related objects to entity in Entity Framework 4.1
 singulars
 PostTypePostTypeId
 PTQuestion
PostTypePostTypeId
1. PTAnswer
UserLastEditorUserId
1. This table or related slice is empty.
UserOwnerUserId
1. USSlauma
plurals
PostLinksPostIdRelatedPostId
1. This table or related slice is empty.
PostLinksRelatedPostIdPostId
1. This table or related slice is empty.
PostsAcceptedAnswerId
1. POentity object cannot be referenced by multiple instances of IEntityChangeTracker. while adding related objects to entity in Entity Framework 4.1
 singulars
 PostTypePostTypeId
 PTQuestion
PostsParentIdCreationDate
1. This table or related slice is empty.
VotesPostIdCreationDate
1. VO
 singulars
 PostPostId
 PO
 UserUserId
 This table or related slice is empty.
 VoteTypeVoteTypeId
 VTAcceptedByOriginator
2. VO
 singulars
 PostPostId
 PO
 UserUserId
 This table or related slice is empty.
 VoteTypeVoteTypeId
 VTUpMod
3. VO
 singulars
 PostPostId
 PO
 UserUserId
 This table or related slice is empty.
 VoteTypeVoteTypeId
 VTUpMod
CommentsPostId
1. This table or related slice is empty.

Querying!

Guidance

A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.