Here, I won't explain what are Caliburn and PostSharp. Their respective documentations, examples and samples already do that very well. But I will show you how to create an aspect which will be applied by PostSharp on the view models of a WPF assembly.
And as a result, on runtime, each time a public property will be changed, the event PropertyChanged of the interface INotifyPropertyChanged will be fired, and the WPF view will be able to refresh its state.
If you already know PostSharp, or have been on their website, you have certainly noticed that they already propose an aspect which intends to implement the interface INotifyPropertyChanged, and to call PropertyChanged when the value of a property is changed.
And if you already know Caliburn, you know that the classes you must inherit from to implement your view models inherit themselves from an abstract class named PropertyChangedBase, which implements INotifyPropertyChanged, and which proposes a function named NotifyOfPropertyChange, to which you give as a parameter the name of the modified property.
The aspect I'm going to show you will allow us to mix these 2 methods.