EntityState.Modify вместо Delete в моей базе данных

Я использую AuditTrail для ведения журнала, но у меня проблема. Я пробовал этот метод;

http://kamoga.net/audit-trail-and-entity-change-tracking-using-entity-framework-dbcontext/

Но я не удаляю запись для операций удаления. У меня есть столбец IsDeleted, и я установил для него значение true.

Если я использую EntityState.Modified в своем ActionResult, в моем столбце Action будет установлено значение U, но я хочу установить D в базе данных.

 [HttpPost, ActionName("Delete")]
        public ActionResult DeleteConfirmed(int id)
        {

            dbContext = new dbContext();

            Gallery gallery = dbContext.Gallery.Find(id);                
            gallery.IsDeleted = true;  
            dbContext.Entry(gallery).State = System.Data.Entity.EntityState.Modified;
       dbContext.SaveChanges();
}

Мой Enum;

public enum AuditActions
{
    I,
    U,
    A
}

AuditTrail.cs;

public class AuditTrail
{
    public int Id { get; set; }
    public string TableName { get; set; }
    public string UserName { get; set; }
    public string Actions { get; set; }
    public string OldData { get; set; }
    public string NewData { get; set; }
    public string ChangedColums { get; set; }
    public string TableIdValue { get; set; }

}

AuditFactoryTrail.cs;

public AuditTrail GetAudit(DbEntityEntry entry)
    {
        AuditTrail audit = new AuditTrail();
        audit.UserName = "Current User";     //You can pass the current user as a parameter
        audit.TableName = GetTableName(entry);
        audit.TableIdValue = GetKeyValue(entry);

        //entry is Added 
        if (entry.State == EntityState.Added)
        {
            var newValues = new StringBuilder();
            SetAddedProperties(entry, newValues);
            audit.NewData = newValues.ToString();
            audit.Actions = AuditActions.I.ToString();
        }
        //entry in deleted
        else if (entry.State == EntityState.Deleted)
        {
            var oldValues = new StringBuilder();
            SetDeletedProperties(entry, oldValues);
            audit.OldData = oldValues.ToString();
            audit.Actions = AuditActions.D.ToString();
        }
        //entry is modified
        else if (entry.State == EntityState.Modified)
        {
            var oldValues = new StringBuilder();
            var newValues = new StringBuilder();
            SetModifiedProperties(entry, oldValues, newValues);
            audit.OldData = oldValues.ToString();
            audit.NewData = newValues.ToString();
            audit.Actions = AuditActions.U.ToString();

            var modifiedProperties = entry.CurrentValues.PropertyNames.Where(propertyName => entry.Property(propertyName).IsModified).ToList();
            var properties = string.Join("||", modifiedProperties.ToList());
            audit.ChangedColums = properties;

        }

        return audit;
    }

    private void SetAddedProperties(DbEntityEntry entry, StringBuilder newData)
    {
        foreach (var propertyName in entry.CurrentValues.PropertyNames)
        {
            var newVal = entry.CurrentValues[propertyName];
            if (newVal != null)
            {
                newData.AppendFormat("{0} = {1} || ", propertyName, newVal);
            }
        }
        if (newData.Length > 0)
            newData = newData.Remove(newData.Length - 3, 3);
    }

    private void SetDeletedProperties(DbEntityEntry entry, StringBuilder oldData)
    {
        DbPropertyValues dbValues = entry.GetDatabaseValues();
        foreach (var propertyName in dbValues.PropertyNames)
        {
            var oldVal = dbValues[propertyName];
            if (oldVal != null)
            {
                oldData.AppendFormat("{0} = {1} || ", propertyName, oldVal);
            }
        }
        if (oldData.Length > 0)
            oldData = oldData.Remove(oldData.Length - 3, 3);
    }

    private void SetModifiedProperties(DbEntityEntry entry, StringBuilder oldData, StringBuilder newData)
    {
        DbPropertyValues dbValues = entry.GetDatabaseValues();
        foreach (var propertyName in entry.OriginalValues.PropertyNames)
        {
            var oldVal = dbValues[propertyName];
            var newVal = entry.CurrentValues[propertyName];
            if (oldVal != null && newVal != null && !Equals(oldVal, newVal))
            {
                newData.AppendFormat("{0} = {1} || ", propertyName, newVal);
                oldData.AppendFormat("{0} = {1} || ", propertyName, oldVal);
            }
        }
        if (oldData.Length > 0)
            oldData = oldData.Remove(oldData.Length - 3, 3);
        if (newData.Length > 0)
            newData = newData.Remove(newData.Length - 3, 3);

    }

    private string GetKeyValue(DbEntityEntry entry)
    {
        var objectStateEntry = ((IObjectContextAdapter)context).ObjectContext.ObjectStateManager.GetObjectStateEntry(entry.Entity);
        string id = "0";
        if (objectStateEntry.EntityKey.EntityKeyValues != null)
            id = objectStateEntry.EntityKey.EntityKeyValues[0].Value.ToString();

        return id;
    }

    private string GetTableName(DbEntityEntry dbEntry)
    {
        TableAttribute tableAttr = dbEntry.Entity.GetType().GetCustomAttributes(typeof(TableAttribute), false).SingleOrDefault() as TableAttribute;
        string tableName = tableAttr != null ? tableAttr.Name : dbEntry.Entity.GetType().Name;
        return tableName;
    }

    private EntityObject CloneEntity(EntityObject obj)
    {
        DataContractSerializer dcSer = new DataContractSerializer(obj.GetType());
        MemoryStream memoryStream = new MemoryStream();

        dcSer.WriteObject(memoryStream, obj);
        memoryStream.Position = 0;

        EntityObject newObject = (EntityObject)dcSer.ReadObject(memoryStream);
        return newObject;
    }
}

DbContext.cs;

 public override int SaveChanges()
    {
        var auditFactory = new AuditTrailFactory(this);



        var entityList = ChangeTracker.Entries().Where(p =>
        p.State == EntityState.Added ||                
        p.State == EntityState.Deleted ||               
        p.State == EntityState.Modified ||              
        !(p.Entity is AuditTrail) ||                    
        p.Entity != null);                           

        entityList.ToList().ForEach(entity =>
        {
            AuditTrail audit = auditFactory.GetAudit(entity);
            AuditTrail.Add(audit);                          
        });

        return base.SaveChanges();
    }