Disabling Entity Framework proxy creation

Question

From what I've read, setting ProxyCreationEnabled = false will prevent change tracking and lazy loading. However, I'm not clear on what change tracking covers.

If I disable it and get an entity from the database, make changes to it and commit, then those changes are saved. I'm also still able to get modified entries from the ChangeTracker:

ChangeTracker.Entries<IAuditable>().Where(x => x.State == EntityState.Modified).ToList()

Should this be possible when I've disabled proxy creation? I want to disable it, but I want to be clear on what I'm disabling.

Sampath · Accepted Answer · 2016-11-15 17:34:48Z

Change tracking and Proxy Creation is two different scenarios. If you need to disable the change tracking then you have to do it as shown below.

public class YourContext : DbContext 
{ 
    public YourContext() 
    { 
        this.Configuration.AutoDetectChangesEnabled = false; 
    }  
}

Then you cannot do this ChangeTracker.Entries<IAuditable>().Where(x => x.State == EntityState.Modified).ToList().

If you need to disable the Proxy Creation then you have to to do it on the constructor of your context as shown below.

public class YourContext : DbContext 
{ 
    public YourContext() 
    { 
        this.Configuration.ProxyCreationEnabled = false; 
    }  

    public DbSet<Blog> Blogs { get; set; } 
    public DbSet<Post> Posts { get; set; } 
}

Proxy creation mechanism is used to support lazy loading of relationships. EF will not create proxies for types where there is nothing for the proxy to do. In other words if you don't have virtual properties on your POCO classes then there is no effect either you have disabled it or not.

If you’re serializing your entities, then consider switching off proxies and lazy loading since deserializing proxies can be tricky.

You can read more about it here : Entity Framework Working with Proxies

Rudi Visser · Accepted Answer · 2016-11-15 17:42:08Z

I can confirm that setting ProxyCreationEnabled to false in EF does not affect Change Tracking. You actually intrigued me with this question as I thought I knew the answer, but to confirm I created a quick test case.

See below example code that represents a valid scenario:

namespace EFCTTest
{
    class Program
    {
        static void Main(string[] args)
        {
            var context = new MyContext();
            context.Tests.First().Test = "Edited";

            var models = context.ChangeTracker.Entries<TestModel>().Where(x => x.State == EntityState.Modified).ToList();
            foreach(var model in models)
                Console.WriteLine($"From {model.OriginalValues["Test"]} to {model.CurrentValues["Test"]}");

            Console.ReadLine();
        }
    }

    public class MyContext : DbContext
    {
        public MyContext()
        {
            Configuration.ProxyCreationEnabled = false;
        }

        public DbSet<TestModel> Tests { get; set; }
    }

    public class TestModel
    {
        public int Id { get; set; }
        public string Test { get; set; }
    }
}

The only thing that disabling proxy generation should affect is the lazy loading functionality of EF when you are using virtual navigation properties to another model. The Change Tracker is independent and works from the underlying ObjectContext itself.

For a complete answer related to change tracking, it's probably worth noting that AutoDetectChangesEnabled appears to be the only setting that would directly affect change tracking functionality, requiring you to call DetectChanges() if you needed to use your sample code.

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