WPF DataGrid 中文怎么按拼音首字母排序

WPF Datagrid点击表头排序是按编码排序的，怎么改成按拼音首字母排序？

示例代码：

    ObservableCollection<Name> names = new ObservableCollection<Name>();
    public MainWindow()
    {
        InitializeComponent(); 
        names.Add(new Name { FirstName = "盼晴", LastName = "刘" });
        names.Add(new Name { FirstName = "小柳", LastName = "张" });
        names.Add(new Name { FirstName = "环", LastName = "伊" });
        names.Add(new Name { FirstName = "冰岚", LastName = "宁" });
        dataGrid.ItemsSource = names;
    }
    public class Name
    {
        public string FirstName { get; set; }
        public string LastName { get; set; }
    }

    <DataGrid Name="dataGrid" ItemsSource="{Binding}"/>

分别点击表头排序后：

• FirstName：B冰岚 - X小柳 - H环 - P盼晴（应该是B-H-P-X）
• LastName：Y伊 - L刘 - N宁 - Z张（应该是L-N-Y-Z）

如何按拼音首字母排序？