Thanks for your feedback, we appreciated this. So far, in the ViewModel base class there are two ways to notify when a property has changed:
- You could pass an Expression, so reflection is used to manage the property name.
- The second option is to notify the property name by passing a string directly.
As you mentioned, the former option is more expensive than the second one, but you still can use the other approach. Anyway, take into account that these are the first drops of Prism v4, and that all the feedback received will be undergo in next drops and
obviously for the final release.
Using the first approach is easier for refactorings and less error prone (as you will get compilation errors if you misspell the property name).
On the other hand, the product team has not detected performance issues using the lambda expressions approach so far.
Therefore, if you experience in your project any performance issue, you could send this feedback since it will be really important for the product team.
Please let me know if this helps.