public override void OnPropertyChanged(PropertyChangedEventArgs e)
        {
            base.OnPropertyChanged(e);

            switch (e.PropertyName)
            {
            case "file":
            case "ImageFileName":
                this.BackgroundImage = TargaImage.LookupFile(this, TypedSerializationObject.file);
                break;
            }
        }
        protected override void OnUpdateControl()
        {
            base.OnUpdateControl();

            this.BackgroundImage = TargaImage.LookupFile(this, TypedSerializationObject.file);
        }