如何在WPF中不重复值的情况下将数字绑定到DataGridComboBoxColumn

<DataGrid>
    <DataGrid.Columns>
        <DataGridComboBoxColumn Header="数字列" SelectedItemBinding="{Binding Number}">
            <DataGridComboBoxColumn.ElementStyle>
                <Style TargetType="ComboBox">
                    <Setter Property="ItemsSource" Value="{Binding DataContext.Numbers, RelativeSource={RelativeSource AncestorType=DataGrid}}"/>
                </Style>
            </DataGridComboBoxColumn.ElementStyle>
            <DataGridComboBoxColumn.EditingElementStyle>
                <Style TargetType="ComboBox">
                    <Setter Property="ItemsSource" Value="{Binding DataContext.Numbers, RelativeSource={RelativeSource AncestorType=DataGrid}}"/>
                </Style>
            </DataGridComboBoxColumn.EditingElementStyle>
        </DataGridComboBoxColumn>
    </DataGrid.Columns>
</DataGrid>

public class ViewModel : INotifyPropertyChanged
{
    private ObservableCollection<int> numbers;
    public ObservableCollection<int> Numbers
    {
        get { return numbers; }
        set
        {
            numbers = value;
            OnPropertyChanged(nameof(Numbers));
        }
    }

    public ViewModel()
    {
        Numbers = new ObservableCollection<int>(GetUniqueNumbers());
    }

    private List<int> GetUniqueNumbers()
    {
        // 返回不重复的数字列表
    }

    // 实现INotifyPropertyChanged接口的代码
}