running in new thread mvvm light C#

public class MainViewModel : ViewModelBase
{
  public const string StatusPropertyName = "Status";
  private bool _condition = true;
  private RelayCommand _startSuccessCommand;
  private string _status;
  public RelayCommand StartSuccessCommand
  {
    get
    {
      return _startSuccessCommand
        ?? (_startSuccessCommand = new RelayCommand(
          () =>
          {
            var loopIndex = 0;
            ThreadPool.QueueUserWorkItem(
              o =>
              {
                // This is a background operation!
                while (_condition)
                {
                  // Do something
                  DispatcherHelper.CheckBeginInvokeOnUI(
                    () =>
                    {
                      // Dispatch back to the main thread
                      Status = string.Format("Loop # {0}", 
                         loopIndex++);
                    });
                  // Sleep for a while
                  Thread.Sleep(500);
                }
              });
          }));
    }
  }
  public string Status
  {
    get
    {
      return _status;
    }
    set
    {
      Set(StatusPropertyName, ref _status, value);
    }
  }
}