How to give positive and negative values set different colors.
ChartView can do it?
<chart:RadCartesianChart x:Name="chart1" Width="1725" Height="176" TrackBallLineStyle="{StaticResource trackBallLineStyle}" Grid.RowSpan="2" Loaded="chart1_Loaded">                        <chart:RadCartesianChart.TrackBallInfoStyle>                            <Style TargetType="chartView:TrackBallInfoControl">                                <Setter Property="Template">                                    <Setter.Value>                                        <ControlTemplate TargetType="chartView:TrackBallInfoControl">                                            <StackPanel Name="panel">                                            </StackPanel>                                        </ControlTemplate>                                    </Setter.Value>                                </Setter>                            </Style>                        </chart:RadCartesianChart.TrackBallInfoStyle>                        <chart:RadCartesianChart.Behaviors>                            <chartView:ChartTrackBallBehavior ShowIntersectionPoints="False" />                        </chart:RadCartesianChart.Behaviors>                        <chartView:AreaSeries CategoryBinding="Time" ValueBinding="Data"  Fill="#FFCC80"  Stroke="#FF9900" StrokeThickness="2"  ItemsSource="{Binding DemoList}" Loaded="AreaSeries_Loaded">                            <chartView:AreaSeries.TrackBallInfoTemplate>                                <DataTemplate>                                    <StackPanel Orientation="Vertical" Margin="0,0,0,20">                                        <Border Background="#666666" Width="65" Height="20" CornerRadius="3" HorizontalAlignment="Center" VerticalAlignment="Center">                                            <TextBlock Text="{Binding DataPoint.Value}" FontSize="14" FontFamily="Segoe UI" Foreground="White" HorizontalAlignment="Center" VerticalAlignment="Center"/>                                        </Border>                                        <Path HorizontalAlignment="Center" VerticalAlignment="Center" Height="6" Width="14" Stretch="Fill" Opacity="1" Data="M 25,22 C25,22 39,22 39,22 39,22 32,28 32,28 32,28 25,22 25,22 z" Fill="#666666" Margin="0,2,0,0"/>                                    </StackPanel>                                </DataTemplate>                            </chartView:AreaSeries.TrackBallInfoTemplate>                        </chartView:AreaSeries>                        <chart:RadCartesianChart.HorizontalAxis>                            <chartView:DateTimeContinuousAxis MajorStepUnit="Month"                                                          MajorStep="3"                                                LabelFormat="yyyy年MM月dd日"                                                LabelInterval="1" FontFamily="Segoe UI"                                                PlotMode="OnTicks" />                        </chart:RadCartesianChart.HorizontalAxis>                        <chart:RadCartesianChart.VerticalAxis>                            <chartView:LinearAxis Minimum="-3000"                                    MajorStep="1000"                                    Maximum="3000" FontFamily="Segoe UI" MajorTickStyle="{StaticResource tickStyle}" LabelStyle="{StaticResource yLableStyle}">                            </chartView:LinearAxis>                        </chart:RadCartesianChart.VerticalAxis>                        <chart:RadCartesianChart.Grid>                            <chartView:CartesianChartGrid MajorLinesVisibility="X" MajorXLineDashArray="7,3" StripLinesVisibility="Y">                                <chartView:CartesianChartGrid.MajorXLineStyle>                                    <Style TargetType="{x:Type Line}">                                        <Setter Property="Stroke" Value="#CCCCCC"/>                                    </Style>                                </chartView:CartesianChartGrid.MajorXLineStyle>                                <chartView:CartesianChartGrid.YStripeBrushes>                                    <SolidColorBrush Color="Transparent" />                                    <SolidColorBrush Color="#EDEDED" Opacity="0.5" />                                </chartView:CartesianChartGrid.YStripeBrushes>                            </chartView:CartesianChartGrid>                        </chart:RadCartesianChart.Grid>                    </chart:RadCartesianChart>