How do I access the AccordionItems of an Accordion programatically?

Question

I am using an accordion in my silverlight app. In the accordionItem I am having a listbox and I need to access the expanded accordion item and this listbox of the accordion.

I am having hard time finding accessing the accordionitem and the listbox it is holding. How do I do this?

What I tried to solve it is to use the following extension class:

public static IEnumerable<DependencyObject> GetVisuals(this DependencyObject root)
{
  int count = VisualTreeHelper.GetChildrenCount(root);
  for (int i = 0; i < count; i++)
  {
    var child = VisualTreeHelper.GetChild(root, i);
    yield return child;
    foreach (var descendants in child.GetVisuals())
    {
      yield return descendants;
    }
  }
}

and then call it for my accordion:

    foreach (var control in MyAccordion.GetVisuals().OfType<ListBox>())
    {
      // Do something with the listbox 
    }

Unfortunately, even without the OfType extension method the Accordion reports to have 0 when GetChildrenCount is called inside the extension method.

UPDATE:

I found a way to access the AccordionItem using the following code

    int selectedIndex = OrganiChartAccordion.SelectedIndex;
    AccordionItem accordionItem = OrganiChartAccordion.ItemContainerGenerator.ContainerFromIndex(selectedIndex) as AccordionItem;

In the AccordionItem I am using a DataTemplate to render the data. In the DataTemplate I have two listboxes. I need to access the data template in the accordionitem that is selected and inside the datatemplate the two listbox.

score 2 · Answer 1 · answered Dec 19 '12 at 09:01

Try this:

<UserControl x:Class="SilverlightApplication10.MainPage"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
             xmlns:layout="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Layout.Toolkit"
             mc:Ignorable="d"
             d:DesignHeight="300"
             d:DesignWidth="400">

    <Grid x:Name="LayoutRoot"
          Background="White">
        <layout:Accordion x:Name="Accordion1">
            <layout:Accordion.Items>
                <layout:AccordionItem Header="Header 1">
                    <ListBox>
                        <ListBox.Items>
                            <ListBoxItem Content="Item 1"></ListBoxItem>
                            <ListBoxItem Content="Item 2"></ListBoxItem>
                            <ListBoxItem Content="Item 3"></ListBoxItem>
                        </ListBox.Items>
                    </ListBox>
                </layout:AccordionItem>
                <layout:AccordionItem Header="Header 2">
                    <ListBox>
                        <ListBox.Items>
                            <ListBoxItem Content="Item 1"></ListBoxItem>
                            <ListBoxItem Content="Item 2"></ListBoxItem>
                            <ListBoxItem Content="Item 3"></ListBoxItem>
                        </ListBox.Items>
                    </ListBox>
                </layout:AccordionItem>
            </layout:Accordion.Items>
        </layout:Accordion>
    </Grid>
</UserControl>

And the code-behind:

using System;
using System.Diagnostics;
using System.Linq;
using System.Windows;
using System.Windows.Controls;

namespace SilverlightApplication10
{
    public partial class MainPage : UserControl
    {
        public MainPage()
        {
            InitializeComponent();

            this.Loaded += MainPage_Loaded;
        }

        void MainPage_Loaded(object sender, RoutedEventArgs e)
        {
            Accordion1.Items.ToList().ForEach(item =>
                {
                    ((item as AccordionItem).Content as ListBox).Items.ToList().ForEach(listBoxItem =>
                        {
                            var content = ((ListBoxItem)listBoxItem).Content;

                            Debug.WriteLine(content);
                        });
                });
        }
    }
}

Thanks for the answer. In my case it is a little more difficult. I use a container style to style the accordionitem and it has a control. When I try to cast the items to that control it returns null for some reason. — gyurisc, Dec 19 '12 at 09:59
I might need to rephrase my question, because it does not explain my problem very well. Sorry for that :) — gyurisc, Dec 19 '12 at 10:00
No problem, just post some more code and I will see if I can help. — Henrik Söderlund, Dec 19 '12 at 10:57
I updated my question, with extra details. In my accordion items I am not placing the listbox controls directly, but defining them in a DataTemplate. My problem is really accessing the DataTemplate nad its content - my listboxes! — gyurisc, Dec 20 '12 at 11:42
Ok, I think I get what you are trying to do. The question is, what exactly do you want to do with the listboxes? If, for example, you want to check what is selected in those listboxes, there are probably better ways to go about it, such as binding the SelectedItem of the listboxes to a property on your data objects. Then you can check that property on the data object instead. If you could add some information about what you are trying to achieve it will be easier to point you in the right direction. — Henrik Söderlund, Dec 20 '12 at 12:13

How do I access the AccordionItems of an Accordion programatically?

1 Answers1