Question

I’m using this ObservableCollection-Class within my Project: Link
I want to Bind a RibbonMenuButton to a ObservableDictionary<string,bool>:

<r:RibbonMenuButton ItemsSource="{Binding MyDictionary}">
    <r:RibbonMenuButton.ItemContainerStyle>
        <Style TargetType="{x:Type r:RibbonMenuItem}">
            <Setter Property="IsCheckable" Value="true"/>
            <Setter Property="Header" Value="{Binding Path=Key}"/>
            <Setter Property="IsChecked" Value="{Binding Path=Value}"/>
        </style>
    </r:RibbonMenuButton.ItemContainerStyle>
</r:RibbonMenuButton>

But I get exceptions because the Value-Properties of the internal IDictionary-KeyValuePairs are readonly. Any Idea how to solve this?

I thought about something like:

<Setter Property="IsChecked" Value="{Binding Source=MyDictionary[{Binding Path=Key}]}"/>

But this won’t work ’cause of {Binding} in {Binding}…

Answer 1

This doesn’t work, because your dictionary isn’t treated as a dictionary but as an IEnumerable<KeyValuePair<string, bool>>. So each RibbonMenuItem is bound to a KeyValuePair<string, bool> with readonly properties Key and Value.
You can do two one things:

1. Use an ObservableCollection<Tuple<string, bool>> instead of the dictionary and bind IsChecked to Item2.
2. Create a little helper class that contains a IsChecked property and change your dictionary to contain that class as the value and bind IsChecked to Value.IsChecked.

I would go with answer two, because the needed changes and possible side effects are smaller.
My answer assumes that you want to have a two way binding on IsChecked. If not, go with the answer of slugster.