protected virtual void ChangeVisualState( bool useTransitions )
{
VisualStateManager.GoToState( this, IsBusy ? VisualStates.StateBusy : VisualStates.StateIdle, useTransitions );
VisualStateManager.GoToState( this, IsContentVisible ? VisualStates.StateVisible : VisualStates.StateHidden, useTransitions );
}