WPF XAML DataGrid填充子DataGrid

<DataGrid AutoGenerateColumns="False" ItemsSource="{Binding MainData}">
    <DataGrid.Columns>
        <!-- 其他列定义 -->
        <DataGridTemplateColumn Header="子DataGrid">
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <DataGrid ItemsSource="{Binding SubData}" AutoGenerateColumns="False">
                        <!-- 子DataGrid的列定义 -->
                    </DataGrid>
                </DataTemplate>
            </DataGridTemplateColumn.CellTemplate>
        </DataGridTemplateColumn>
    </DataGrid.Columns>
</DataGrid>

public class MainViewModel : INotifyPropertyChanged
{
    private ObservableCollection<MainDataModel> mainData;
    public ObservableCollection<MainDataModel> MainData
    {
        get { return mainData; }
        set
        {
            mainData = value;
            OnPropertyChanged(nameof(MainData));
        }
    }

    public MainViewModel()
    {
        MainData = new ObservableCollection<MainDataModel>
        {
            new MainDataModel
            {
                // 其他属性赋值
                SubData = new ObservableCollection<SubDataModel>
                {
                    // 子DataGrid的数据赋值
                }
            }
        };
    }

    // INotifyPropertyChanged接口实现
}

public class MainDataModel
{
    // 主DataGrid的属性
    public ObservableCollection<SubDataModel> SubData { get; set; }
}

public class SubDataModel
{
    // 子DataGrid的属性
}