Updating GUI by changing the model directly

I am experimenting with DataBinding

I have a MainWIndow with a username and password LineEdit a submit button, I have a backend struct for my model, I could confirm that the struct is being updated, but I could not get how could I update the struct and notify the GUI to update the view.

How can I update the View

(I am coming from WPF INotifyPropertyChanged, so maybe I am thinking wrong.)