Hi Dave,

In your settings form create a public/protected property for each of the  
parameters (or group of parameters) you want to display.  Set the values  
the constructor or as separate properties.  When closing  
(DialogResult.OK/Yes etc) update the main form properties.

This sample will open up an OptionDialog in the Options method of  
MainClass.  It will then set the initial properties before displaying, and  
retrieve the these properties if the user clicks OK (assuming it will fire  
DialogResult.OK).

public MainClass
{

    private void Options()
    {
        OptionDialog od = new OptionDialog();
        od.Left = graphStart.Left;
        od.Top = graphStart.Left;
        od.GraphName = "Hello World";

        if(od.ShowDialog() == DialogResult.OK)
        {
            graphStart = new Point(od.Left, od.Top);
            graphName = od.GraphName;
        }
    }
}

public OptionDialog
{
    private TextBox leftBox;
    private TextBox topBox;
    private TextBox graphBox;

    public int Left
    {
        get
        {
            return Int32.Parse(leftBox.Text); // you might want to try/catch
        }
        set
        {
            leftBox.Text = value.ToString();
        }
    }

    // same with top and graph (int/string)
}