How to clone/duplicate an entity?

Question

 

What's the best way to read and object from the store, clone it, and insert the new object as an identical copy (with same references)?

Answer 1

This is the best way I know of at this time:

 

Code Snippet

private static T DataContractSerialization<T>(T obj) {
    DataContractSerializer dcSer = new DataContractSerializer(obj.GetType());
    MemoryStream memoryStream = new MemoryStream();

    dcSer.WriteObject(memoryStream, obj);
    memoryStream.Position = 0;

    T newObject = (T)dcSer.ReadObject(memoryStream);
    return newObject;
}

 

 

 

Answer 2

There are more efficient ways to do it (that i.e. do not end up creating 3 copies in memory), but arguably they are much more complicated.

Answer 3

Matthieu Mezil has written something for cloning entities

 

http://msmvps.com/blogs/matthieu/archive/2008/05/31/entity-cloner.aspx

 

It's a lot of code and he's using Reflection not MetadataWorkspace . I'm sure there's a reason for that. Either way, the code is available on his blog and it's something you can use generically.

 

If you look a little later in his blog, you'll see he modified it to accommodate graphs.

 

 

Answer 4

Hi

In fact, I use reflection because my first idea was to do a cloner for everything (not only for entities).

What is cool on my Cloner is the fact that I use reflection only once per entity type.

"To clone an entity, I use reflection but the problem of Reflection is it’s far. The way to Clone a product is always the same. So I generate a Delegate on the fly during first call and I always use it."

Answer 5

Hi Patrick,

The code snippet which u proposed was not useful when I am trying to clone an Lazy Loaded object.

Can you provide me the solution for this problem???

Answer 6

This is a great series of articles: http://msdn.microsoft.com/en-US/data/jj592677

To quote the above line:

using (var context = new BloggingContext())
{
    var blog = context.Blogs.Find(1);
 
    var clonedBlog = (Blog)context.Entry(blog).GetDatabaseValues().ToObject();
}

Note the original line was as follows but you need the cast (as is shown above):

    var clonedBlog = context.Entry(blog).GetDatabaseValues().ToObject();

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Jan Narkiewicz