Common List Binding Accordion in Silverlight

Question

Given a list of objects containing two properties (IdentityType and Name) in the format:

IdentityType | Name
A | One  
A | Two  
A | Three  
B | Four  
B | Five  
C | Six  

Is there a way to declaratively bind data so that the accordion is displayed as follows?

A
- One
- Two
- Three
B
- Four
- Five
C
- Six

So far, the best I can get is a title bar for each item, for example:

<toolkit:Accordion ItemsSource="{Binding Path=Identities}" Grid.Row="2" SelectionMode="ZeroOrMore">
        <toolkit:Accordion.ItemTemplate>
            <DataTemplate >
                <TextBlock Text="{Binding IdentityType, Converter={StaticResource EnumDescriptionConverter}}"/>
            </DataTemplate>
            </toolkit:Accordion.ItemTemplate>
            <toolkit:Accordion.ContentTemplate>
            <DataTemplate>
                <StackPanel Margin="5" Orientation="Horizontal">
                    <TextBlock Text="{Binding Name}" Foreground="White" />
                </StackPanel>
            </DataTemplate>
        </toolkit:Accordion.ContentTemplate>
    </toolkit:Accordion>

I'm new to Silverlight, so I might have missed something dazzlingly obvious, but any help would be greatly appreciated!

Answer 1

You can do this using a view model between your model (initialization list) and your view (markup).

• Create a view model class with title Title and NameCollection
• LINQ ( foreach), 6 3 3, 2 1 .
• AccordionsSource ViewModel.
• Title
• , ItemsControl, .
• NamesCollection

, :

public class Model
{
    public string Title { get; set; }
    public string Name { get; set; }
}

...

public class ViewModel
{
    public string Title { get; set; }
    public List<string> Names { get; set; }
}

public class DataContextClass
{
    public DataContextClass()
    {
        var modelData = new ModelData();

        var query = from m in modelData.ModelCollection
                    group m by m.Title
                    into vm select new ViewModel { Title = vm.Key, Names = vm.Select(x => x.Name).ToList() };
        ViewModelCollection = query.ToList();
    }

    public List<ViewModel> ViewModelCollection { get; set; }
}

DataContextClass, DataContext ...

<layout:Accordion ItemsSource="{Binding Path=ViewModelDataInstance.ViewModelCollection}" >
    <layout:Accordion.ItemTemplate>
        <DataTemplate>
            <TextBlock Text="{Binding Title}" />
        </DataTemplate>
    </layout:Accordion.ItemTemplate>
    <layout:Accordion.ContentTemplate>
        <DataTemplate>
            <ItemsControl ItemsSource="{Binding Path=Names}" />
        </DataTemplate>
    </layout:Accordion.ContentTemplate>
</layout:Accordion>

Answer 2

Tuple. :

public class DataContextClass{
public DataContextClass()
{
    var modelData = new ModelData();

    var query = from m in modelData.ModelCollection
                group m by m.Title
                into vm select Tuple.Create(vm.Key,  vm.Select(x => x.Name).ToList() };
    Collection = query.ToList();
}

public Tuple<string,List<string>> Collection { get; set; }

}

Xaml :

<layout:Accordion ItemsSource="{Binding Path=ViewModelDataInstance.ViewModelCollection}" >
<layout:Accordion.ItemTemplate>
    <DataTemplate>
        <TextBlock Text="{Binding Item1}" />
    </DataTemplate>
</layout:Accordion.ItemTemplate>
<layout:Accordion.ContentTemplate>
    <DataTemplate>
        <ItemsControl ItemsSource="{Binding Path=Item2}" />
    </DataTemplate>
</layout:Accordion.ContentTemplate>

,