public void saveChanges()
        {
            using (var db = new PlanningContext())
            {
                history_event data = null;

                if (!this._isCreateMode)
                {
                    var id = Convert.ToInt32(this.history_event_id.Text);
                    data = db.history_event.Where(d => d.history_event_id == id).FirstOrDefault();
                    if (data == null)
                    {
                        this._mainInterface.statusText = $"ERROR: ID '{this.history_event_id.Text}' does not exist.";
                        return;
                    }
                }
                else
                {
                    data = new history_event();
                }

                data.history_event_id = Convert.ToInt32(this.history_event_id.Text);
                data.description      = /**/ (this.description.Text);
                data.is_active        = (bool)this.is_active.IsChecked;


                if (this._isCreateMode)
                {
                    db.history_event.Add(data);
                }
                db.SaveChanges();
            }
        }
        public void deleteItem(object item)
        {
            if (item == null)
            {
                return;
            }

            history_event data = item as history_event;

            if (data == null)
            {
                return;
            }

            using (var db = new PlanningContext())
            {
                db.history_event.Remove(db.history_event.Where(d => d.history_event_id == data.history_event_id).First());
                db.SaveChanges();
            }
        }