by Mikael Henriksson
29. May 2009 02:56
In previous post I wrote a minor struggle about POCO. I was reading like a few 100 blog posts about EF4 and came across an interesting post about lazy loading by Julie Lerman. I agree with Rob that lazy loading should be possible to set for a specific collection and I am sure this will be possible in the future but for now we will have to do without I think. My take on it is to allow this to be set in the constructor of the CustomContext. I’ll use an enum for this for now:
public enum Options
{
None = 0,
LazyLoading = 1,
ProxyCreation = 2,
All = LazyLoading | ProxyCreation
}
Now I can set this straight away. Since I hate code duplication I created a couple of private methods so I don’t have to make mistakes while ctrl+c + ctrl+v.
public class EntityContext : System.Data.Objects.ObjectContext
{
public ObjectSet<User> Users { get; set; }
public ObjectSet<Blog> Blogs { get; set; }
public ObjectSet<Post> Posts { get; set; }
public EntityContext()
: base("name=Entities", "Entities")
{
CreateObjectSets();
}
public EntityContext(Options options)
: base("name=Entities", "Entities")
{
CreateObjectSets();
SetContextOptions(options);
}
private void SetContextOptions(Options options)
{
switch (options)
{
case Options.All:
this.ContextOptions.DeferredLoadingEnabled = true;
this.ContextOptions.ProxyCreationEnabled = true;
break;
case Options.LazyLoading:
this.ContextOptions.DeferredLoadingEnabled = true;
break;
case Options.ProxyCreation:
this.ContextOptions.ProxyCreationEnabled = true;
break;
case Options.None:
this.ContextOptions.DeferredLoadingEnabled = false;
this.ContextOptions.ProxyCreationEnabled = false;
break;
default:
break;
}
}
private void CreateObjectSets()
{
this.Users = CreateObjectSet<User>();
this.Blogs = CreateObjectSet<Blog>();
this.Posts = CreateObjectSet<Post>();
}
}Now I can go ahead and create my EntityContext with providing the desired options in the constructor:
var context = new EntityContext(Options.LazyLoading);
If it is performance we are after then another option would be what Alex suggests in this specific post of his series of tips regarding EF4.
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