Adding existing entity to navigation property of a different entity

Posted by Shay Friedman on Stack Overflow See other posts from Stack Overflow or by Shay Friedman
Published on 2010-05-09T14:38:57Z Indexed on 2010/05/09 14:48 UTC
Read the original article Hit count: 502

Filed under:

entity-framework

I'm using EF4 and I'm running into a problem when I try to do something that looks quite trivial to me.

I have two entities, let's call them A and B. These entities have a many-to-many association between them with a navigation property on A that contains a list of related B entities.

What I want to do is to add existing B entities to a new A entity. When I try to do that, I get an exception:

AcceptChanges cannot continue because the object's key values conflict with another object in the ObjectStateManager. Make sure that the key values are unique before calling AcceptChanges.

Has anyone run into such a problem?

Related posts about entity-framework

Differences Between NHibernate and Entity Framework

as seen on ASP.net Weblogs - Search for 'ASP.net Weblogs'
Introduction NHibernate and Entity Framework are two of the most popular O/RM frameworks on the .NET world. Although they share some functionality, there are some aspects on which they are quite different. This post will describe this differences and will hopefully help you get started with the one… >>> More
Entity Framework & Binding syncronisation

as seen on Stack Overflow - Search for 'Stack Overflow'
* EDIT * Sorry, I should make it clearer. Imagine I have an entity: public class MyObject { public string Name { get; set; } } And I have a ListBox: <ListBox x:Name="lbParts"> <ListBox.ItemTemplate> <DataTemplate> <TextBlock Text="{Binding Name}"/> … >>> More
Joins and UI Binding with the Entity Framework

as seen on Internet.com - Search for 'Internet.com'
Learn how to build queries with the Entity Framework that involve multiple tables as well as binding in the UI with the EntityDataSource. >>> More
Frederick .NET User Group April 2010 Meeting

as seen on Geeks with Blogs - Search for 'Geeks with Blogs'
FredNUG is pleased to announce that we have an excellent speaker lined up for April. On April 20th, we’ll start with pizza and social networking at 6:30 PM. Then, starting at 7 PM, Dane Morgridge will present “Getting Started with Entity Framework 4” The scheduled agenda is: 6:30 PM - 7:00… >>> More
[News] NHibernate vs MS Entity Framework

as seen on Dot Net Guru - Search for 'Dot Net Guru'
Voil? une question qui se posera de plus en plus avec la sortie prochaine de .NET V4 et Entity Framework V4, l'outil de mapping objet/relationnel de Microsoft. M?me s'il est vrai que l'opinion de Ayende peut para?tre biais?e du fait qu'il est contributeur NHibernate, son point de vue et surtout ses… >>> More

Developer IT

Adding existing entity to navigation property of a different entity - Developer IT

Adding existing entity to navigation property of a different entity

entity-framework

Related posts about entity-framework

Differences Between NHibernate and Entity Framework

Entity Framework & Binding syncronisation

Joins and UI Binding with the Entity Framework

Frederick .NET User Group April 2010 Meeting

[News] NHibernate vs MS Entity Framework

Categories cloud