public ChangeStatusDialogViewModel(RequestServiceImpl.RequestService requestService, int requestId)
{
_requestService = requestService;
_requestId = requestId;
StatusList = new ObservableCollection <StatusDto>(_requestService.GetRequestStatuses());
var request = _requestService.GetRequest(_requestId);
_oldStatusId = request.State.Id;
SelectedStatus = StatusList.SingleOrDefault(s => s.Id == request.State.Id);
Refresh(null);
}