Deep LINQ projections, how? - linq

Question

Let's say I have a model created with EF 4.0
User
Roles
Permissions
Each entity has a DeleteDate property.
I want to get a specific user (with Name =...) and have the tree filled with items where DeletedDate == null..
This must be done with anonymous type projection as result, but I don't know how to accomplish this with a hierachy deeper than 2..
This is what I already have:
public MyProjection MyCall(string givenName)
{
var result = from s in context.Users
where (s.Name == givenName &&
s.DeletedDate == null)
select new
{
s,
roles = from r in s.Roles
where r.DeletedDate == null
select r
};
var outcome = result.FirstOrDefault();
if (outcome != null)
{
var myProjection = new MyProjection()
{
User = outcome.s,
Roles = outcome.roles
};
return myProjection;
}
return null;
}

Answer 1

Depending on your structure you could do something like this:
var result = m.Users.Where(u => u.DeletedDate == null)
.Select( u => new
{
u,
roles = u.Roles.Where(r => r.DeletedDate == null)
.Select(r => new
{
r,
permissions = r.Permissions.Where(p => p.DeletedDate == null)
})
}).FirstOrDefault(item => item.u.Name == givenName);

Answer 2

If you retrieve with the following:
var result = from s in MyUsers
where s.DeletedDate == null
select new aUser{
Roles = (from r in s.Roles
where r.DeletedDate == null
select r).ToList()
};
And then create a TreeView:
TreeView treeView = new TreeView();
Then set the ItemsSource of the TreeView to the IEnumerable:
treeView.ItemsSource = result;
Then build a HierarchicalDataTemplate in your TreeView to represent your Lists (similar to this or for more in depth this), then voila!