How to set a border on a list box item

Question

I have a ListBox in which the items are created from an item source, I need every item to have a border but I have no clue where I even set a style for ListBox items.

<ListBox x:Name="m_list">
    <ListBox.ItemTemplate>
        <DataTemplate>
            <Expander IsExpanded="True">
                <CustomUserControl />
            </Expander>
        </DataTemplate>
    </ListBox.ItemTemplate>
    <ListBox.ItemsSource>
        <Binding Path="DataToBeEditied" />
    </ListBox.ItemsSource>
</ListBox>

The custom user controls are a user control I created which edit the data from DataToBeEdited which is an ObservableCollection of data

According to what I can find there should be a way but no explanation on how. How Do I do it?

Answer 1

You could define an ItemContainerStyle:

<ListBox>
    <ListBox.ItemContainerStyle>
        <Style TargetType="ListBoxItem">
            <Setter Property="BorderThickness" Value="2" />
            <Setter Property="BorderBrush" Value="Red" />
        </Style>
    </ListBox.ItemContainerStyle>
</ListBox>