有一段代码，Y轴坐标是对应的，可是X轴坐标不对应，是什么问题？各位大神。

WPF toolkit 。Y轴坐标是对应的，可是X轴坐标不对应，是什么问题？

<toolkitchart:ScatterSeries ItemsSource="{Binding ChartModel1}"
DependentValueBinding="{Binding Value}"
IndependentValueBinding="{Binding Key}"
Title="(xi,yi)" IsSelectionEnabled="True" >
<toolkitchart:ScatterSeries.DataPointStyle>
<Style BasedOn="{StaticResource MyScatterDataPointStyle}" TargetType="{x:Type toolkitchart:ScatterDataPoint}">
<Setter Property="Background" Value="Brown"/>
<Setter Property="Width" Value="10"/>
<Setter Property="Height" Value="10"/>
</Style>
</toolkitchart:ScatterSeries.DataPointStyle>
</toolkitchart:ScatterSeries>

ChartModel1.Add(new ChartModel
{
Key = kvp.Key+"",
Value = kvp.Value,
LevelText = "第"+i+"天测试序号"+j,
Figure = decimal.Parse(kvp.Value.ToString("0.00")),
CreatTime = DateTime.Now
});