It looks that you have absolutely no idea what you are doing.
First,
read some documentation about WPF Binding https://msdn.microsoft.com/en-us/library/ms752347.aspx[
^] - how it works, what is binding target, binding source and how should it be used. Articles about MVVM sure come in handy.
The main problem (from the code you provided) is that the
NumOrd
property should be on the
Model_Ricerca_Dati_Viaggio
class, since DataGrid is bound to the collection of
Model_Ricerca_Dati_Viaggio
s.
Then, you don't need to explicitly invoke none of the OnPropertyChanged in your button click event handler.
Don't forget to set the control's DataContext to the instance of class, which contains
Dati_Viaggio
and
SelectDati_Viaggio
properties.
Good habbit is to write code in english and not your native language.
Also by convention, .NET clases should not contain underscores (_).