Soft-Delete and Entity Framework

It is very common to find enterprise applications where entities shouldn't be removed from the database, but just "marked" as deleted. If you are using Entity Framework, you can use the following approach. I hope this post helps you!

Firstly, we need to identify which entities are the ones that should support the soft-delete behavior. In order to do that we can use the following interface:

public interface ISoftDeleteEntity
{
    bool Deleted { get; set; }
}

We can use partial classes in order to implement the interface, so there is no need to modify the auto-generated classes.

public partial class Customer : ISoftDeleteEntity
{
}

Finally, we need to override the SaveChanges of the ObjectContext in order to get the deleted entities and run the soft-delete logic.

public partial class DatabaseEntities
{
    public override int SaveChanges(SaveOptions options)
    {
        var deletedEntities = GetDeletedEntities();

        SoftDelete(deletedEntities);

        return base.SaveChanges(options);
    }

    private List<ISoftDeleteEntity> GetDeletedEntities()
    {
        return ObjectStateManager
            .GetObjectStateEntries(EntityState.Deleted)
            .Select(entry => entry.Entity)
            .OfType<ISoftDeleteEntity>()
            .ToList();
    }

    private void SoftDelete(List<ISoftDeleteEntity> deletedEntities)
    {
        deletedEntities.ForEach(e =>
        {
            ObjectStateManager.ChangeObjectState(e, EntityState.Modified);
            e.Deleted = true;
        });
    }
}

As you can see in the code snippet, first of all we are obtaining all the entities that are going to be deleted and that implement the ISoftDeleteEntity interface. After that, we are changing their state to modified and setting the Deleted property.

Note: If the changes were not detected yet (WCF DataServices scenario), you should call the DetectChanges method before obtaining the deleted entities. The attached source code shows how to do it.

You can download the sample code from here.