Thank you for your feedback Kamlendra!

I am glad that this approach helped you.

HI maria,

it worked. Thanks a lot!!
The issue was: using the behavior twice(in zoom char and zoombar as well).i was using it once only. so the Chart object was null in the behavior class. now its resolved.

Thanks again!!

Regards,

Kamlendra

hi maria,

thanks for your reply!! i am trying it.

Regards,

kamlendra

Kamlendra, 

The chart displayed in XamZoomBar is a preview of the chart that is bound to XamZoomBar. The preview chart (the one in the zoombar) displays all data while the other one shows only the zoomed area. This allow user to know which part of the chart is actually zoomed in. If you need, you can zoom in or out the preview chart, too. I have modified the sample application that was uploaded to this thread by adding interaction behavior to the xmPreviewDataChart chart so the displayed data is modified when the thumb size is changed.  

Hello Maria,

i will try to summarize and explain again: 

"From the pictures it seems that not all data points are displayed in the chart located in the zoombar. Is that the issue on your side? "::
 ----- the issue is other way. in my zoomBar i am able to see all data. but it should only specific zoomed data.
you can find out from the name of my images:
Current: Currentoutput-onloadWithoutclickonZoombar-showingallValuesfromStart.png
Expected:  ExpectedOutput-afterClickonZoomBar-showingOnlyZoomedValues.png

**the issue only persist until user click the zoombar. because "this.Chart.WindowRectChanged " is not getting registered. 
so, in my view the only issue is WindowRectChanged event registration.

(Explaining Again)i feel the only culprit in this problem is : initially this.Chart object is getting null so this.Chart.WindowRectChanged event never getting registered.

i am using 2 chart objects. 
1) <ig:XamDataChart x:Name="xmDataChart" DataContext=...  (for lower part, big chart in image)
2) (The Other one is child of zoombar in HorizontalPreviewContent) which is synchronized with the main (Name:"xmDataChart")
 <ig:XamZoombar Name="xamZoombar1" VerticalAlignment="Top" Background="Transparent" Margin="5,5,50,5"

Range="{Binding ElementName=xmDataChart, Path=HorizontalZoombar.Range, Mode=TwoWay}"
Opacity=".8">

<ig:XamZoombar.HorizontalPreviewContent>
<ig:XamDataChart DataContext="{Binding

Is this causing the this.Chart object in the behaviour class as null and not registring the event this.Chart.WindowRectChanged .

 Regards,
Kamlendra