Null Conditional Operator

Also known as Null-Propagation operator

return myvalue?.SubString(0,5); 

Instead of

string smaller = myvalue; 
if (myvalue != null) 
{ 
   smaller = myvalue.SubString(0,5); 
} 
return smaller 

PropertyChanged?.Invoke(propertyChanged(this, new PropertyChangedEventArgs(nameof(Name));