Background: Interceptors in EF6 vs EF Core

FeatureEF Core (Modern)EF6 (in .NET Framework)
Interceptor support | AddInterceptors() (per context) | DbInterception.Add() (global)
Dependency Injection | Built-in with IServiceCollection | Manual or via DI container
SaveChanges Auditing | Supported via SaveChanges() | Supported via SaveChanges()

Goal

Recreate this EF Core-style setup in EF6:

services.AddSingleton<UpdateAuditableInterceptor>();
services.AddSingleton<InsertOutboxMessagesInterceptor>();

services.AddDbContext<IApplicationDbContext, ApplicationDbContext>(
    (sp, options) => options
        .UseSqlServer(connectionString)
        .AddInterceptors(...));

Step 1: Define EF6 Interceptors

In EF6, you can create interceptors by implementing interfaces like IDbCommandInterceptor.

public class UpdateAuditableInterceptor : IDbCommandInterceptor
{
    public void ReaderExecuting(DbCommand command, DbCommandInterceptionContext<DbDataReader> interceptionContext)
    {
        // Add your auditing logic here
    }

    // You can leave the rest of the methods empty if not needed
    public void NonQueryExecuting(...) { }
    public void ScalarExecuting(...) { }
    // etc.
}

You can do the same for your InsertOutboxMessagesInterceptor.

Step 2: Register Interceptors with EF6

EF6 does not support context-scoped interceptors. Instead, use the static DbInterception class:

Option A: Global Registration in Global.asax.cs

protected void Application_Start()
{
    DbInterception.Add(new UpdateAuditableInterceptor());
    DbInterception.Add(new InsertOutboxMessagesInterceptor());
}

Option B: Register via Dependency Injection

If you’re using Microsoft.Extensions.DependencyInjection (or any DI container), you can do this:

var services = new ServiceCollection();

services.AddSingleton<UpdateAuditableInterceptor>();
services.AddSingleton<InsertOutboxMessagesInterceptor>();

services.AddScoped<ApplicationDbContext>(provider =>
{
    var interceptor1 = provider.GetRequiredService<UpdateAuditableInterceptor>();
    var interceptor2 = provider.GetRequiredService<InsertOutboxMessagesInterceptor>();

    DbInterception.Add(interceptor1);
    DbInterception.Add(interceptor2);

    return new ApplicationDbContext("YourConnectionString");
});

⚠️ Important: EF6 interceptors are global and affect all DbContext instances in the AppDomain.

Bonus: SaveChanges Auditing Without Interceptors

For simple audit tracking like setting UpdatedAt timestamps, it's better to override SaveChanges() in your context:

public override int SaveChanges()
{
    var entries = ChangeTracker.Entries<IAuditableEntity>();

    foreach (var entry in entries)
    {
        if (entry.State == EntityState.Modified)
        {
            entry.Entity.UpdatedAt = DateTime.Now;
        }
    }

    return base.SaveChanges();
}

This is cleaner, more predictable, and avoids EF6 interceptor quirks.

Testing It All

Make sure to test with:

• Inserts and updates for auditable entities
• Scenarios where interceptors may not fire (e.g., raw SQL)
• Multi-threaded contexts if using global interceptors

Summary

You can mimic EF Core's AddInterceptors() in EF6, but with some caveats:

• Interceptors are global in EF6.
• Manual DI setup is required.
• For auditing, overriding SaveChanges() is often simpler and safer.

If you're maintaining a .NET Framework project but want to adopt some clean patterns from EF Core, this approach will help bridge that gap.