Can you update the value of an ItemsSource item from the control?

Question

Say, for example, I have a ListBox.  The ListBox has it's ItemsSource bound to some data object behind the scenes.  Is it possible to change the actual value of a data item behind the scenes by changing it's associated bound ListBoxItem content/text?

I would think that in theory two-way binding would work here ... but some preliminary tests seem to not be working.  Am I missing something, or is two way binding not applicable in this case?

Answer 1

You have to implement INotifyPropertyChanged in your  model object and raise NotifyPropertyChanged from the properties of your model. It is the way that WPF listen changes.

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http://weblogs.asp.net/marianor/

Answer 2

Hi Mariano - that's a good point, however I unfortunately don't have access to the underlying data model that drives the ItemsSource.  This is a custom control I'm building that builds off a ListBox.  So I know the ItemsSource, but users of the control actually provide the data object behind the scenes which I have no idea about.

Any other way to accomplish this?

Answer 3

Consumer of your control will normally bind to the SelectedXXX properties to update their model.

Answer 4

You can make a wrapper over that class and raise the property changed. Other option is refresh the binding when you know you have a change.

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http://weblogs.asp.net/marianor/

Answer 5

Refreshing the binding ... that's a possibility, I'll try that.

You mentioned making a wrapper for the class ... which class are u referring to?

Answer 6

I'm referin to the class that you are using to bound the items. You can use som patterns to do that, for example MVVM.

http://msdn.microsoft.com/en-us/magazine/dd419663.aspx

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http://weblogs.asp.net/marianor/