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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
Category : 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

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Replacing a child entity in an entity collection that is attached to a parent entity (Master detail scenario)
Category : 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


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Entity Framework - inserting new entity via objectcontext does not use existing entity properties
Category : 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

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entity framework compare in memory entity to saved entity
Category : 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

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Entity Framework: Update Entity when Another Entity is Updated
Category : 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


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Entity Framework: Assign entity to property of another entity
Category : 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
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How to Add existing entity as a new Entity with Entity Framework
Category : 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

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Entity Framework Multiple Table to Single Entity isnt querying both tables
Category : Programming Languages

I have a Article and Blog tables that I want to represent as a Content Entity. I have mapped both tables to the Content entity however when I query using a ObjectSet.Take(20) only the article table is being hit in the dbase. Am i wrong in thinking (hoping) the query should look where contentType = 1 and 2?


Ta


SQL query looks like this...


SELECT
[Exte

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General persist method in Entity Framework - inserting or updating (if exists) entity
Category : Programming Languages

What is the best solution in entity framework to implement generic persist method?


For example there is a Company entity:


public class Company
{
public Company()
{
Id = Guid.NewGuid();
}
public Guid Id { get; set; }
public string Name { get; set; }
}

The Id property can be generat


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Generating Integer Identity Primary Key for Entity Object in Entity Framework and SQL Server CE
Category : Programming Languages

I heard that this issue is fixed in SQL Server Compact Edition 4.0 CTP


As recently I just stepped into SQL Server CE and Entity Framework, and VS2010 not yet supporting SQL Server CE 4.0


I think I would need a work around for this issue


Can I know how to generate an Integer type Identity Primary Key inside the constructor of the Entity Object



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