Question

I have an instance of ObservableCollection bound to a WPF listbox with two separate data templates (one for display, one for editing). The data template for editing has a one-way binding on the textbox, and a Save button.

What changes do I need to make so that when I press the Save button (after putting the list item in edit mode), the value I change the textbox to replaces the value in the ObservableCollection (and the display)?

Answer 1

Items in your collection should be of type that implements INotifyPropertyChanged interface. This way your list box will be notified that property value in your single item object has changed. ObservableCollection raises CollectionChanged event only when collection changes (items added, removed, etc.)

Quote from the MSDN library article on ObservableCollection

To fully support transferring data
values from binding source objects to
binding targets, each object in your
collection that supports bindable
properties must implement an
appropriate property changed
notification mechanism such as the
INotifyPropertyChanged interface.