difficulty cloning object without saving changes to it.

[Stacey]

I have a situation where I need to copy an object from the database into another object, and then make changes to the copied version. But I am ending up with a problem, because it persists changes back to the original.

This is the method I am using to make a copy;

/// <summary>

/// Perform a deep Copy of the object, using Json as a serialisation method.

/// </summary>

/// <typeparam name="T">The type of object being copied.</typeparam>

/// <param name="source">The object instance to copy.</param>

/// <returns>The copied object.</returns>

public static T Clone<T>(this T source) {

// Don't serialize a null object, simply return the default for that object

if (Object.ReferenceEquals(source, null)) {

return default(T);

}

// initialize inner objects individually

// for example in default constructor some list property initialized with some values,

// but in 'source' these items are cleaned -

// without ObjectCreationHandling.Replace default constructor values will be added to result

var deserializeSettings = new JsonSerializerSettings { ObjectCreationHandling = ObjectCreationHandling.Replace };

return JsonConvert.DeserializeObject<T>(JsonConvert.SerializeObject(source), deserializeSettings);

}

And then I'll use it like this;

var clone = aspect.Clone<Aspect>();
    clone.Name = "New Name";

When I run this and go to the studio UI, some of the objects in the collection yield errors when I try to open them. If I do not have the copy, this does not occur.

[Stacey]

Sorry, I forgot to add - when I clone the object and make changes, the changes do not persist back to the original, but I think something changes because the original seems to vanish from the database, but there is like a "ghost copy" left behind of it, that I cannot open. I'm at a complete loss as to what is happening, this method is the only thing I can trace the behavior back to.

[Federico Lois]

Use evict. In that way you are disconnecting the original object from the tracking of the session and treat it a new one.

---

From: Stacey
Sent: ‎16/‎01/‎2016 19:52
To: RavenDB - 2nd generation document database
Subject: [RavenDB] Re: difficulty cloning object without saving changes to it.

Sorry, I forgot to add - when I clone the object and make changes, the changes do not persist back to the original, but I think something changes because the original seems to vanish from the database, but there is like a "ghost copy" left behind of it, that I cannot open. I'm at a complete loss as to what is happening, this method is the only thing I can trace the behavior back to.

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[Oren Eini (Ayende Rahien)]

session.Advanced.Evict() is a method that will cause the session to forget about your object

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On Tue, Feb 2, 2016 at 1:18 PM, Stacey <stacey.ci...@gmail.com> wrote:

I'm not clear what "evict" is. Is this a method or something in Raven?