How to get a List<string> collection of values from app.config in WPF?

The following example fills the ItemsControl with a List of BackupDirectories which I get from code.

How can I change this so that I get the same information from the app.config file?

XAML:

<Window x:Class="TestReadMultipler2343.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="300" Width="300">
    <Grid Margin="10">
        <Grid.RowDefinitions>
            <RowDefinition Height="30"/>
            <RowDefinition Height="Auto"/>
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="120"/>
            <ColumnDefinition Width="160"/>
        </Grid.ColumnDefinitions>
        <TextBlock 
            Grid.Row="0"
            Grid.Column="0"
            Text="Title:"/>
        <TextBlock 
            Grid.Row="0"
            Grid.Column="1" 
            Text="{Binding Title}"/>
        <TextBlock 
            Grid.Row="1"
            Grid.Column="0"
            Text="Backup Directories:"/>
        <ItemsControl 
            Grid.Row="1"
            Grid.Column="1"
            ItemsSource="{Binding BackupDirectories}"/>
    </Grid>
</Window>

code-behind:

using System.Collections.Generic;
using System.Windows;
using System.Configuration;
using System.ComponentModel;

namespace TestReadMultipler2343
{
    public partial class Window1 : Window, INotifyPropertyChanged
    {

        #region ViewModelProperty: Title
        private string _title;
        public string Title
        {
            get
            {
                return _title;
            }

            set
            {
                _title = value;