public void UpdateDriveAvailable() { List <string> listOfAvailableDrive = new List <string>(); while (!_stopThread) { if (listOfAvailableDrive.Count != DriveManager.GetAllDrive().Count) { listOfAvailableDrive = DriveManager.GetAllDrive(); DriveLetter = new ObservableCollection <string>(listOfAvailableDrive); } Thread.Sleep(100); } }