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I am new to the Entity Framework and have the following problem:

I get a list of objects from the ObjectContext (RepEntities) which is used to populate a grid. The grid allows users to modify and select the binded objects. Once this is done I add the selected objects to another parent object. The issue is that when a property is changed for a specific object it also changes the property in other parent objects which have the same selected child object. Therefore, the ObjectSet returns a reference to the same objects each time.

I solved my issue by manually cloning the objects in the ObjectSet as follows: 

public List<mblDataItem> GetSupportDataItems()
{
    var items= (from e in RepEntities.jblDatItemDatTypes
             where e.mblDataType.dtDsc == "Support"
             select e.mblDataItem).OrderBy(p => p.diDsc).ToList();
    mblDataItem di;
    List<mblDataItem> diItems = new List<mblDataItem>();
    foreach (var item in items)
    {
        di = new mblDataItem();
        di.diID = item.diID;
        di.diDsc = item.diDsc;
        di.diSQL = item.diSQL;
        di.Influence = item.Influence;
        di.Comment = item.Comment;
        di.PrimValue = item.PrimValue;
        di.CompValue = item.CompValue;
        diItems.Add(di);
    }
    return diItems; 
}


What is the proper way of cloning/duplicating the ObjectSet ? Also, the way I am doing it I will not be able to use the navigation properties to get related entities.

UPDATE:

Ok, so I tried doing it as explained on Cloning an Entity in Linq-to-Entities and suggested by Schwarzie2478.

This does not work for me as I need to clone more than one object. What I need is to have a multiple collections of mblDataItems whose properties can be set independently from each other but still have the same EntityKey, so that inserts are done correctly. I also noticed that my first solution is flawed, because when I call SaveChanges() it inserts additional mblDataItems and then uses the newly inserted IDs in my joining table, instead of the existing mblDataItem IDs. What am I doing wrong?

Ewald Stieger
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  • Are all your entities seriazable? I've used serialization before to clone objects. I'm not sure if this is the best solution, but it involves less code that can break when you change entities... – Schwarzie2478 Feb 09 '12 at 09:59
  • possible duplicate of [Clone Self-Tracking Entities in EF 4.0?](http://stackoverflow.com/questions/8406359/clone-self-tracking-entities-in-ef-4-0) – Magnus Feb 09 '12 at 10:49
  • @Schwarzie2478: You mean like this: `public static T Clone(this T source) { var dcs = new System.Runtime.Serialization .DataContractSerializer(typeof(T)); using (var ms = new System.IO.MemoryStream()) { dcs.WriteObject(ms, source); ms.Seek(0, System.IO.SeekOrigin.Begin); return (T)dcs.ReadObject(ms); } }` ? I got this from [Cloning an Entity in Linq-to-Entities](http://naspinski.net/post/Cloning-an-Entity-in-Linq-to-Entities.aspx) – Ewald Stieger Feb 09 '12 at 10:49

0 Answers0