如何将布尔值绑定到wpf中的组合框

<ComboBox IsChecked="{Binding IsSelected}">
    <ComboBox.Items>
        <ComboBoxItem>选项1</ComboBoxItem>
        <ComboBoxItem>选项2</ComboBoxItem>
        <ComboBoxItem>选项3</ComboBoxItem>
    </ComboBox.Items>
</ComboBox>

public class ViewModel : INotifyPropertyChanged
{
    private bool _isSelected;

    public bool IsSelected
    {
        get { return _isSelected; }
        set
        {
            if (_isSelected != value)
            {
                _isSelected = value;
                OnPropertyChanged(nameof(IsSelected));
            }
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;

    protected virtual void OnPropertyChanged(string propertyName)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

public MainWindow()
{
    InitializeComponent();
    DataContext = new ViewModel();
}