Communicate between two windows forms in C#

Question

I have two forms, one is the main form and the other is an options form. So say for example that the user clicks on my menu on the main form: Tools -> Options

Answer 1

You can have a function in Form B like so:

public SettingsResults GetNewSettings()
{
    if(this.ShowDialog() == DialogResult.Ok)
    {
         return new SettingsResult { ... };
    }
    else
    {
         return null;
    }
}

And you can call it like this:

...
using(var fb = new FormB())
{
    var s = fb.GetNewSettings();
    ...
    // Notify other parts of the application that settings have changed.
}