Update Detached entity in EF 6

Question

I'm new to Entity Framework and I'm using Mock to test my repository. The repository uses a class that implements DbContext.

When I run the update test on a tracked entity, it works fine but when I do it on a detached one, it doesn't update the entity.

I currently use the method Attach to update it. I even tried other methods below but no success. I need advice on that.

myContext.Set<Blog>().Attach(detachedBlog);

Entry<Blog>(myBlog).State = EntryState.Modified;

Entry<Blog>(existingBlog).CurrentValues.SetValues(detachedBlog);

Answer 1

I'm not sure what your question is.  Could you clarify?

David

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David http://blogs.msdn.com/b/dbrowne/

Answer 2

The question is how do I update the database using a detached entity with Entity Framework 6.

Knowing that my database already has a record ( Id = 1, Name = "New Blog"), how do I use the code below to update it without having to update every property separately?

Blog detachedBlog = new Blog() { Id = 1, Name = "New Blog Again" };

using (var ctx = new BlogDBEntities())
{
  ctx.Blogs.Attach(detachedBlog);
  ctx.SaveChanges();
}


                
        
        

Answer 3

In EF 6 you can just set the state of the entity to modified and then save it.

Blog detachedBlog = new Blog() { Id = 1, Name = "New Blog Again" };

using (var ctx = new BlogDBEntities())
{
  ctx.Entry(detachedBlog).State = EntityState.Modified;  
  ctx.SaveChanges();
}

Answer 4

When I run my unit test on it I get a null pointer exception. My unit Test is mocking BlogDBEntities. I'm not sure if that's the reason

Answer 5

Hello Ken Taps,

>> When I run my unit test on it I get a null pointer exception. My unit Test is mocking BlogDBEntities. I'm not sure if that's the reason

Please try a simple console application to call the BlogDBEntities to check if you would still encounter a null pointer exception.                                                                                                                      

Regards.

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