CODEWITHSUNDEEP
c#wpf
NicolasR
NicolasR

Reputation: 2312

WPF monitoring property changes

I frequently have the following task:

I have a collection of objects (f.e. Customers) and want to provide the user with an editor for these objects. Typically I have some list control on the left side of the editor and a form on the right side. The form displays the properties of the object that is currently selected on the left side.

Regarding the confirmation of any changes, there are at least two strategies:

My question is about the second strategy, implemented as an MVVM application with WPF:

I would like to give my user a feedback that there are unsaved changes. Applications like text editors often solve this by enabling the Save button when any changes occurred and disabling it again once the user pressed it to confirm her/his changes.

If I understand correctly I would have to monitor changes to any bound properties in my form (backed by a model class). Usually my model classes use auto properties (no explicit getters and setters). Do I have to write explicit getters for all my properties to enable the Save button when anything changed, or is there a smarter way to achieve this?

Upvotes: 3

Views: 280

Answers (2)

Pavel Anikhouski
Pavel Anikhouski

Reputation: 23228

Following the MVVM pattern, your ViewModels should implement INotifyPropertyChanged interface, than you can easily subscribe to PropertyChanged event and monitor properties changes

Upvotes: 4

GazTheDestroyer
GazTheDestroyer

Reputation: 21251

If you don't want to write INPC aware getters and setters in your model classes, then another way is to write a equality compare method instead, and then have your save command availability callback call into that to compare the "live" object with the edited one. I'm assuming you have a cloned object that is being edited in order to rollback if the user chooses not to save.

WPF will call it automatically as the user clicks around and types, or you can give it a hint with CommandManager.InvalidateRequerySuggested()

Upvotes: 1

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