Question

I’m probably missing something obvious due to the late hour.

I have a dictionary defined as such Dictionary<string,MyObject> where MyObject has a property bool IsFavoriate

Initially on page load I query my web service, and update the Dictionary with any new objects and save this in IsolatedStorage.

For the UI, I am binding the Dictionary to an ItemsControl where I have a checkbox:

<ItemsControl ItemsSource="{Binding Categories, Mode=TwoWay}">
     <ItemsControl.ItemTemplate>
          <DataTemplate>
                <CheckBox IsChecked="{Binding Value.IsFavorite}" Content="{Binding Key}" />
          </DataTemplate>
      </ItemsControl.ItemTemplate>
 </ItemsControl>

This binds fine. When I select a checkbox however, I want my Dictionary to update.

Do I perhaps need to have the properties in MyObject call RaisePropertyChanged? Maybe I’ll give that a shot for now.

Answer 1

You would need to implement the INotifyPropertyChanged interface on your MyObject class and raise the PropertyChanged event from your IsFavorite property setter in cases where the latter may be updated programmatically (after the initial population), and you want the IsChecked property (and the CheckBox’s visual state) to be updated with your changes.

In your case, you want updates to be propagated the other way round (from the IsChecked property to IsFavorite); that is typically accomplished by setting the binding to Mode=TwoWay.

<ItemsControl ItemsSource="{Binding Categories, Mode=TwoWay}">
     <ItemsControl.ItemTemplate>
          <DataTemplate>
                <CheckBox IsChecked="{Binding Value.IsFavorite, Mode=TwoWay}"
                          Content="{Binding Key}" />
          </DataTemplate>
     </ItemsControl.ItemTemplate>
</ItemsControl>

P.S. I’m assuming you meant “When I select check a checkbox however, I want my Dictionary to update. ”