Silverlight ListBox Checkbox Selected Item

Question

I have a Listbox, that has a Checkbox as part of the item template.

In the click even of the Checkbox, I want to make sure that same list item is selected.

ListBoxItem lbi = ((ListBoxItem)listLayers.
                       ContainerFromElement((CheckBox)sender));
lbi.IsSelected = true;

The main issue that I'm having is that "ContainerFromElement" is not available in silverlight.

Any help is greatly appreciated.

edit

This is the code I'm running in the click event of a checkbox inside my list:

MyObject obj = listLayers.SelectedItem as MyObject;
obj.Visible = true;
obj.Value = "50";

Using the RelativeSource binding on the checkboxes along with this code, I end up with obj equal to null.

I have a list of layers that I want to turn on and off via checkboxes, I'm open to another way...

Answer 1

In the selectionChanged event you have to "walk" the visual tree to find the checkbox. You can do this by using the VisualTreeHelper

This example show what you need to do to get to the checkbox.

Below are some other solutions to this problem

You should use a RelativeSource binding between the ListboxItem and the CheckBox. The datatemple contains a checkbox. Change it to look like this.

<CheckBox 
  IsChecked="{Binding RelativeSource={RelativeSource TemplatedParent}, 
    Path=IsSelected, Mode=TwoWay}" />

This creates a binding between the IsSelected property of the ListBox and the IsChecked property of the CheckBox. This tutorial explains how with an example.

If you need more control, you should have a look at behaviors and triggers. They're a bit more complex but give you you more control.