Where to place the BackgroundWorker

Question

I have a class that gathers information about a machine (this is an example - in total GetInfo() may take minutes to run):

public class Scanner
{
    public void GetInfo()
    {
        this.Name = GetName();
        this.OS = GetOS();
    }

    public string Name { get; set; }
    public string OS { get; set; }
    public string Status { get; set; }

    private string GetName() { this.Status = "Getting computer name"; /*More operations*/ }
    private string GetOS() { this.Status = "Getting OS"; /*More operations*/ }
}

This is called by a form that needs to provide status feedback to the user.

TextBox1.Text = scanner.Status;

My question is, to achieve this, what is the best way to implement threading so that the application remains responsive?

I have got a BackgroundWorker running in the form and calling GetName(), GetOS() etc itself and that works fine, but the code isn't very repeatable - to keep maintenance low I want to keep a GetInfo() method in the class so if I need to run a scan from elsewhere theres only one piece of code that knows about how to.

I could move the BackgroundWorker in to GetInfo(), but then how would the form be able to check the Status property without doing a loop and locking up the UI?

Maybe have a BackgroundWorker in the form run GetInfo() and then run another Worker that would check Status and update the form if a change is detected?

This is my first proper go at Threading and can't get my head around what, I think, is a fairly common task so any help would be appreciated.

Note: I'm also well open to suggestions for other ways to implement the Status property - hopefully you get what I'm trying to achieve.

/edit: Some clarification.

Scanner.GetInfo() would be called manually, for example on a form button click. GetInfo() would then start populating the objects properties as it goes gathering information, and might take 5 minutes to complete.

I need to be able to keep the user up to date on its status, and the only way I can think of that happening (with my current knowledge) is for GetInfo() to update a 'Scanner.Status' property, which the form can then check at interval/within a loop and update the UI when it changes.

Answer 1

How about using INotifyPropertyChanged with a thread in the class as follows:

public class Scanner : INotifyPropertyChanged
{
  private string _Name, _OS;
  public event PropertyChangedEventHandler PropertyChanged;

  public string Name
  {
    get
    {
      return _Name;
    }
    set
    {
      if (value != _Name)
      {
        _Name = value;
        NotifyPropertyChanged("Name");
      }
    }
  }

  public string OS
  {
    get
    {
      return _OS;
    }
    set
    {
      if (value != _OS)
      {
        _OS = value;
        NotifyPropertyChanged("OS");
      }
    }
  }

  public void GetInfo()
  {
    _Name = string.Empty;
    _OS = string.Empty;

    new Thread(() => this.Name = GetName()).Start();
    new Thread(() => this.OS = GetOS()).Start();
  }

  private void NotifyPropertyChanged(string pName)
  {
    if (PropertyChanged != null)
    {
      PropertyChanged(this, new PropertyChangedEventArgs(pName));
    }
  }

  private string GetName() 
  { 
    return "long name operation here"; 
  }

  private string GetOS()
  {
    return "long OS operation here";
  }
}

Then in your form you could use the following:

Scanner m_Scanner = new Scanner();

public void Main()
{
  m_Scanner.PropertyChanged += UpdateGUI;
  m_Scanner.GetInfo();
}

private void UpdateGUI(object sender, PropertyChangedEventArgs e)
{
  if (e.PropertyName == "OS")
    txtOs.Text = m_Scanner.OS;
  else if (e.PropertyName == "Name")
    txtName.Text = m_Scanner.Name;
}