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entity object cannot be referenced by multiple instances of IEntityChangeTracker. while adding related objects to entity in Entity Framework 4.1
by CurrentlyPissed in Programming Languages

I am trying to save Employee details, which has references with City. But everytime I try to save my contact, which is validated I get the exception "ADO.Net Entity Framework An entity object cannot be referenced by multiple instances of IEntityChangeTracker"


I had read so many post but still not getting the exact idea of what to do...
my Save button click code is given below


Replacing a child entity in an entity collection that is attached to a parent entity (Master detail scenario)
by postino in Development Tools & Services

I have a Self tracking Entity collection (EF 4) in a silverlight 4 project which is accessed and updated via regular WCF 4 Services (Not RIA). Since I cannot indulge in my real scenario for privacy reasons, here is a very similar scenario.


This is like a Customer/Order/OrderStatus scenario. A customer has a one-to-many relationship with orders. Order has an OrderStatus (set via t


Entity Framework - inserting new entity via objectcontext does not use existing entity properties
by eb. in Web Design

I have an insert method on my repository like so:


public T Insert(T entity)
{
_ctx.AddObject(EntityName, entity);
_ctx.SaveChanges();
return entity;
}

If I execute the below code, the values assigned to my entity do not propagate to the SQL that is executed.


Category c = new Category();
c.Name = CLEARA

entity framework compare in memory entity to saved entity
by Matt Watson in Programming Languages

I've simplified my code to better illustrate my point. I need to have some business logic where I test if a property has changed from a to b. The problem that I'm facing is that the entity that I am manipulating is attached to my DBContext. If I update the property on one of my references the other is also updated:


....
var oldEntity = context.Find(x);
var upda

Entity Framework: Assign entity to property of another entity
by cbot5000 in Coding

I have these entities (this is just an abstraction I created for this post):


Language
District
Description

These are the references between them:


District * - 1 Language
Description * - 1 Language
District 1 - 1 Description

If I fetch like this:


var myFetch = from c in context.Districts
where c.Id = 10
Entity Framework: Update Entity when Another Entity is Updated
by Sigtryggur in Programming Languages

I have an EDM, it includes the entities extension and history. My goal is to use history to keep track of all the changes made to extension entity. For example, if extension with ID 223 has its property 'Name_Display' changed - I want the history entity to record this.


I'm using ASP.NET with VB.NET. Where in my code do I put the hook to say, "update the history entity" and what shou


How to Add existing entity as a new Entity with Entity Framework
by Erenhardt in Programming Languages

I want to create a copy my object in my DB with using Entity Framework


first I got my "Book" from DB


var entity1 = new testEntities();
var book= entity1.Books.First();
entity1.Dispose();

then, I tried to add this object as a new object


var entity2 = new testEntities();
book.Id = 0;
entity2.SaveChanges();
ent

Entity Framework 4.1 auto generate with DbContext when creating ADO.NET Entity Data Model
by VulgarDisplay in Programming Languages

I would like to work with DbContext instead of ObjectContext. I updated EF so now I have the DbContext, but I want to generate my strongly-typed context based on the DbContext and not the ObjectContext. When I add new ADO.NET Entity Data Model, it is still based on the ObjectContext. Is it not possible to have it base off of DbContext in Visual Studio 2010 with EF 4.1?


UPDATE:


Entity Framework 4 error: An entity object cannot be referenced by multiple instances of IEntityChangeTracker
by dougbeal in Coding

I am using EF4 for the first time and have adopted a strategy of a UnitofWork (DataContext) per View. However, I am having issues and seek advice.


I have a window that displays a list of workstations, when I click the edit button I have another window that displays the selected workstation for edit.


The list view and the edit view use their own UnitOfWork, the selected w


How to query an Entity Framework entities container for objects of derived entity classes?
by Mcad in Programming Languages

I have a complex inheritance structure in my data model. A majority of classes in my model (which is designed in VS 2010 with a DB generated by it after) are derived from 3 basic classes. And only these 3 classes can be found among the context members. How do I use all the derived classes at all?


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