How to update progress bar from other class?

Question

I have a command line tool written in c# (that i have the source of) that I am making a gui for in visual studio 2010. In the gui I want to update the progress bar to reflect the progress of the tools operations. How would I signal from inside the tool that progress has been made and to update the progress bar? Some simplified example code of what im doing.

private void doThings_Click(object sender, EventArgs e)
{
  myToolInstance.doWorkThatNeedsToReportProgress();
}

The work that is being done by the tool is a series of function calls, normally around 30. I want to update the progress bar each time one of those finishes.

Answer 1

Create a public property or a public method in the form containing the progress bar

public void SetProgress(int progress)
{
    progressBar.Progress = progress;
}

Now you can update the progress bar with

myForm.SetProgress(50);

---

Another approach is to have a ProgressChanged event somewhere and let the form subscribe to this event.

public class Tool {
    public event Action<int> ProgressChanged;

    private void OnProgressChanged(int progress) 
    {
        ProgressChanged?.Invoke(progress);
    }

    public void DoSomething()
    {
        ...
        OnProgressChanged(30);
        ...
    }
}

In the form you would have something like this

private Tool _tool;

public MyForm () // Constructor of your form
{
    _tool = new Tool();
    _tool.ProgressChanged += Tool_ProgressChanged;
}

private void Tool_ProgressChanged(int progress)
{
    progressBar.Progress = progress;
}