Question: I am using EF4 Self Tracking Entities (VS2010 Beta 2 CTP 2 plus new T4 generator). But when I try to update entity information it does not update to database as expected.

I setup 2 service calls. one for GetResource(int id) which return a resource object. the second call is SaveResource(Resource res); here is the code.

```
    public Resource GetResource(int id)
    {
        using (var dc = new MyEntities())
        {
            return dc.Resources.Where(d => d.ResourceId == id).SingleOrDefault();
        }        
    }

    public void SaveResource(Resource res)
    {
        using (var dc = new MyEntities())
        {
            dc.Resources.ApplyChanges(res);
            dc.SaveChanges();
            // Nothing save to database.
        }      
    }

    //Windows Console Client Calls
    var res = service.GetResource(1);
    res.Description = "New Change"; // Not updating...
    service.SaveResource(res); 

    // does not change anything.

```

It seems to me that ChangeTracker.State is always show as "Unchanged".

anything wrong in this code?

Answer: 
You have to share assembly with STEs between client and service - that is the main point. Then when adding service reference make sure that "Reuse types in referenced assemblies" is checked.

The reason for this is that STEs contain logic which cannot be transfered by "Add service reference", so you have to share these types to have tracing logic on client as well.
After reading the following tip from Daniel Simmons, the STE starts tracking. Here is the link for the full article. <http://msdn.microsoft.com/en-us/magazine/ee335715.aspx>

> 
> **Make certain to reuse the Self-Tracking Entity template’s generated entity code on your client.** If you use proxy code generated by Add Service Reference in Visual Studio or some other tool, things look right for the most part, but you will discover that the entities don’t actually keep track of their changes on the client.
> 
> 
> 

so in the client make sure you don't use add service reference to get the proxy instead access service through following code.

```
var svc = new ChannelFactory<IMyService>("BasicHttpBinding_IMyService").CreateChannel();
var res = svc.GetResource(1);

```