Question

I’m using EF 4.1 in POCO mode.

LINQ2SQL generates partial methods on the datacontext that get called when inserting/updated/deleting an entity. They’re helpful for cases like:

    partial void InsertCampaign( Campaign instance )
    {
        instance.CreatedAtUTC = instance.ModifiedAtUTC = DateTime.UtcNow;

        ExecuteDynamicInsert( instance );
    }

    partial void UpdateCampaign( Campaign instance )
    {
        instance.ModifiedAtUTC = DateTime.UtcNow;

        ExecuteDynamicUpdate( instance );
    }

So, my question is — with EF, how do you hook into the inserting/updating/deleting of entities so that you can perform operations such as the above? I would prefer not to have to do this manually every time I create/update an entity.

Thank you

Answer 1

Override SaveChanges() method in your DbContext and do something like:

    public override int SaveChanges()
    {
        var modified = this.ChangeTracker.Entries().Where(e => e.State == System.Data.EntityState.Modified);
        // set whatever values you want on modified entities
        return base.SaveChanges();
    }