How to Bind Checked / Selected Items From CheckListBox in WPF by using MVVM Model (I am using "WPFToolkit.Extended.dll" to get CheckListBox Control)

CheckList Box from WPFToolKit. Below is XAML code (MainWindow.xaml)

<xctk:CheckListBox x:Name="SiteCheckList" Margin="0,0,512,0" Height="100" Width="150"
                               ItemsSource="{Binding SiteList}"
                               DisplayMemberPath="SiteName"
                               CheckedMemberPath="IsChecked">
            </xctk:CheckListBox>

Below Properties added in Model Class. I would like to get Checked Items from CheckListBox to my string List (Model.cs). This string List I will be using for further in project logic.

private string _SiteName;

        public string SiteName
        {
            get { return _SiteName; }
            set { _SiteName = value; }
        }

    private List<string> _SelectedSiteList;
            public List<string> SelectedSiteList
            {
                get { return _SelectedSiteList; }
                set
                {
                    _SelectedSiteList = value;
                }
            }

View Model (ViewModel.cs)

class ViewModel : INotifyPropertyChanged {

    private ObservableCollection<Model> _SiteList;

    public ObservableCollection<DataModel> SiteList
    {
        get { return _SiteList; }
        set { _SiteList = value; }
    }

    public ViewModel()
    {
        SiteList = new ObservableCollection<Model>();
        PoppulateSiteNames();
    }


    private void PoppulateSiteNames()
    {
        Dictionary<string, string> keyValuePairs = new Dictionary<string, string>();
        keyValuePairs = Files.ReadIni_KeyValue("SiteSection");
        foreach (string Key in keyValuePairs.Keys)
        {
            keyValuePairs.TryGetValue(Key, out string LogTable);
            SiteList.Add(new Model() { SiteName = LogTable });
        }

    }

    public event PropertyChangedEventHandler PropertyChanged;

    protected void OnPropertyChanged(string PropertyName)
    {
        if (PropertyChanged !=null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(PropertyName));
        }
    }

}

Here I would like to get list of Checked / Selected Items from UI. If I don't want to write any code in MainWindow.cs i.e. CheckedChanged event then How I can do it by using Binding method ?

Updated Model Class with IsChecked Boolean Property.

private bool _IsChecked;

        public bool IsChecked
        {
            get { return _IsChecked; }
            set { _IsChecked = value; }
        }

Then ViewModel Updated with Below Function to Populate SiteList

 private void PoppulateSiteNames()
        {
            Dictionary<string, string> keyValuePairs = Files.ReadIni_KeyValue(Vars.MSSQL_Section);
            string [] Sites = keyValuePairs.Values.ToArray();
            for (int i = 0; i < Sites.Length; i++)
            {
                SiteList.Add(new HistoricalDataModel { SiteName = Sites[i] });
            }
        }

Now, Finally I got CheckedItems in below Variable using LINQ

var checkedSites = from site in SiteList
                                where (site.IsChecked == true)
                                select new { site.SiteName };

Thank you all of you for responding my question and triggering me to think more.