在Livecharts WPF中使用DateTime

<Grid>
    <lvc:CartesianChart Width="500" Height="300" Series="{Binding ChartSeries}" LegendLocation="Right" >
        <lvc:CartesianChart.AxisX>
            <lvc:Axis Title="时间" Labels="{Binding Labels}" LabelFormatter="{Binding Formatter}"></lvc:Axis>
        </lvc:CartesianChart.AxisX>
        <lvc:CartesianChart.AxisY>
            <lvc:Axis Title="数值"></lvc:Axis>
        </lvc:CartesianChart.AxisY>
    </lvc:CartesianChart>
</Grid>

public class MainViewModel : INotifyPropertyChanged
{
    public SeriesCollection ChartSeries { get; set; }
    public ObservableCollection<string> Labels { get; set; }

    public MainViewModel()
    {
        // 初始化数据
        ChartSeries = new SeriesCollection
        {
            new LineSeries
            {
                Title = "数据系列",
                Values = new ChartValues<double> { 1, 3, 2, 8, 5, 6, 3, 7 },
            }
        };

        // 初始化X轴标签
        Labels = new ObservableCollection<string>
        {
            DateTime.Now.AddDays(-7).ToString("yyyy-MM-dd"),
            DateTime.Now.AddDays(-6).ToString("yyyy-MM-dd"),
            DateTime.Now.AddDays(-5).ToString("yyyy-MM-dd"),
            DateTime.Now.AddDays(-4).ToString("yyyy-MM-dd"),
            DateTime.Now.AddDays(-3).ToString("yyyy-MM-dd"),
            DateTime.Now.AddDays(-2).ToString("yyyy-MM-dd"),
            DateTime.Now.AddDays(-1).ToString("yyyy-MM-dd"),
            DateTime.Now.ToString("yyyy-MM-dd")
        };
    }
}

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        DataContext = new MainViewModel();
    }
}