Hello Bin,

Thank you for posting to Infragistics Community!

I have been looking into your question and I believe you will find the Category Tooltip Layer topic in our documentation very helpful on the matter. The CategoryToolTipLayer displays grouped tooltips for the series on the XamDataChart control using a category axis.

<ig:XamDataChart >
    <!— other configs -->
    <ig:XamDataChart.Axes>
    <!— axes -->
    </ig:XamDataChart.Axes>
    <ig:XamDataChart.Series>
    <!— series -->
        <ig:CategoryToolTipLayer ToolTipPosition="Auto"
                                                               TransitionDuration="0:00:00.1"/>
    </ig:XamDataChart.Series>
</ig:XamDataChart>

Furthermore, by setting the ToolTip object of each series, you could add additional text for each series value.

<ig:LineSeries ItemsSource="{StaticResource data}"
ValueMemberPath="Oil"
XAxis="{Binding ElementName=xAxis}"
YAxis="{Binding ElementName=yAxis}">
    <ig:LineSeries.ToolTip>
        <StackPanel Orientation="Horizontal">
            <TextBlock>Some text:</TextBlock>
            <TextBlock Text="{Binding Item.Oil}" />
        </StackPanel>
    </ig:LineSeries.ToolTip>
</ig:LineSeries>

If this is not an accurate demonstration of what you would like to achieve, please do provide more details regarding the types of series and axes used. Thank you for your cooperation.

Attached you will find a small sample with a XamDataChart displaying several series and demonstrating the CategoryToolTipLayer. Please, test it on your side and if you require any further assistance on the matter, please let me know.

Best regards,
Bozhidara Pachilova
Associate Software Developer

2117.XDCCategoryTooltipLayer.zip