Convert IEnumerable to EntitySet

Question

Hoping somebody can shed some light, and perhaps a possible solution to this issue I'm having...

I have used LINQ to SQL to pull some data from a database into local entities. They are products from a shopping cart system. A product can contain a collection of KitGroups (which are stored in an EntitySet (System.Data.Linq.EntitySet). KitGroups contain collections of KitItems, and KitItems can contain Nested Products (which link back up to the original Product type - so its recursive).

From these entities I'm building XML using LINQ to XML - all good here - my XML looks beautiful, calling a "GenerateProductElement" function, which calls itself recursively to generate the nested products. Wonderful stuff.

However, here's where i'm stuck.. i'm now trying to deserialize that XML back to the original objects (all autogenerated by Linq to SQL)... and herein lies the problem. Linq tO Sql expects my collections to be EntitySet collections, however Linq to Xml (which i'm tyring to use to deserailise) is returning IEnumerable.

I've experimented with a few ways of casting between the 2, but nothing seems to work... I'm starting to think that I should just deserialise manually (with some funky loops and conditionals to determine which KitGroup KitItems belong to, etc)... however its really quite tricky and that code is likely to be quite ugly, so I'd love to find a more elegant solution to this problem.

Any suggestions?

Here's a code snippet:

    private Product GenerateProductFromXML(XDocument inDoc)
{
    var prod = from p in inDoc.Descendants("Product")
        select new Product
        {
            ProductID = (int)p.Attribute("ID"),
            ProductGUID = (Guid)p.Attribute("GUID"),
            Name = (string)p.Element("Name"),
            Summary = (string)p.Element("Summary"),
            Description = (string)p.Element("Description"),
            SEName = (string)p.Element("SEName"),
            SETitle = (string)p.Element("SETitle"),
            XmlPackage = (string)p.Element("XmlPackage"),
            IsAKit = (byte)(int)p.Element("IsAKit"),
            ExtensionData = (string)p.Element("ExtensionData"),
        };

    //TODO: UUGGGGGGG Converting b/w IEnumerable & EntitySet 
    var kitGroups = (from kg in inDoc.Descendants("KitGroups").Elements("KitGroup")
                     select new KitGroup
                                {
                                    KitGroupID = (int) kg.Attribute("ID"),
                                    KitGroupGUID = (Guid) kg.Attribute("GUID"),
                                    Name = (string) kg.Element("Name"),
                                    KitItems = // THIS IS WHERE IT FAILS - "Cannot convert source type IEnumerable to target type EntitySet..."
                                        (from ki in kg.Descendants("KitItems").Elements("KitItem")
                                         select new KitItem
                                                    {
                                                        KitItemID = (int) ki.Attribute("ID"),
                                                        KitItemGUID = (Guid) ki.Attribute("GUID")
                                                    });
                               });

    Product ImportedProduct = prod.First();

    ImportedProduct.KitGroups = new EntitySet<KitGroup>();
    ImportedProduct.KitGroups.AddRange(kitGroups);

    return ImportedProduct;
}
enter code here

I should add that all the entities mentioned here (Product, KitGroup, KitItem, etc) are generated by Linq to SQL - with no mapping back to any other entities (the shopping cart doesn't use entities so they exist in this context only as a means to serialise/deserialise to/from xml and the database. The functionality i'm building is the ability to export a product with all its kitgroups, kitItems and nested products from one environment, and import into another.

Answer 1

Find following link useful.

http://social.msdn.microsoft.com/Forums/en-US/linqprojectgeneral/thread/58c4dcf8-2d89-4a3c-bb30-58c7c15df04b

---

EDIT: in case the above link ever breaks, solution is to create an extension method

public static EntitySet<T> ToEntitySet<T> (this IEnumerable<T> source) where T : class
{
    var es = new EntitySet<T> ();
    es.AddRange (source);
    return es;
}

Subquery can then use .ToEntitySet()

...
(from ki in kg.Descendants("KitItems").Elements("KitItem")
select new KitItem
{
    KitItemID = (int) ki.Attribute("ID"),
    KitItemGUID = (Guid) ki.Attribute("GUID")
}).ToEntitySet();
...