I am not sure if I should post this here or in the webservices forum, but here goes anyway. I am trying to implement webservices between the admin grids and the db server, and I am having a little issue. My basic question is this; is it possible to serialize an entity that has had it's Query set, pass it to a webservice, deserialize it, call load, serialize again, pass it back to the consumer, and deserialize that into an entity? I've tried and I get the "An Entity can only hold 1 record of data" error. Should I be looking at something along these lines instead? I've tried serializing and deserializing bypassing the webservice and I get the same result.

        try
        {
            ExclusionLists obj = new ExclusionLists();
            obj.Query.Where(obj.Query.Id == this.Id);
            ExclusionListsProxyStub proxy = new ExclusionListsProxyStub(obj);
            string data = Utility.SerializeProxy(proxy);
            proxy = (ExclusionListsProxyStub)Utility.DeserializeProxy(data, typeof(ExclusionListsProxyStub));            
            obj = proxy.entity;
            obj.Query.Load();
            return obj;
        }
        catch (Exception)
        {
            throw;
        }

Aren't you mixing scenarios? Maybe I am wrong, but if you want to return a collection, then shouldn't you build a query based on a collection (ExclusionListsCollection version ExclusionLists)?

... just a thought.

A complete test:

// Client-side query to load an Employee
Employee emp = new Employee();
emp.Query.Where(emp.Query.EmployeeID == 1);

// Use binary serialization to include the query
BinaryFormatter bf = new BinaryFormatter();
MemoryStream ms = new MemoryStream();
bf.Serialize(ms, emp);
byte[] query = ms.ToArray();

// Send it to the server over the wire

// Server-side deserialize
bf = new BinaryFormatter();
ms = new MemoryStream(query);
Employee newEmp = bf.Deserialize(ms) as Employee;

// Now load it 
Assert.IsTrue(newEmp.Query.Load());
Assert.AreEqual(1, newEmp.EmployeeID.Value);

//  Server-side Create a Proxy and Serialize to XML string
EmployeeProxyStub proxy =
    new EmployeeProxyStub(newEmp);

XmlSerializer sf =
    new XmlSerializer(typeof(EmployeeProxyStub));
StringWriter sw = new StringWriter();
sf.Serialize(sw, proxy);

string packet = sw.ToString();

// Send it back to the client over the wire

// Client-side Proxy XML string deserialize
XmlSerializer xs =
    new XmlSerializer(typeof(EmployeeProxyStub));
StringReader sr = new StringReader(packet);

proxy = xs.Deserialize(sr) as EmployeeProxyStub;
emp = proxy.Entity;

Assert.AreEqual("Unchanged", emp.es.RowState.ToString());
Assert.AreEqual(1, emp.EmployeeID.Value);