Hi Phuoc,
Sorry for the long delay in getting back to you.
We have prepared the sample for your requirement.Could you please find the samlpe from the below. Try running the sample and let us know if this helps.If still the issue exist, Could you please provide us with the entire sample you are using to reproduce ths issue.So that we can analyse the issue and provide you with clear details.
Sample link:
http://www.syncfusion.com/uploads/redirect.aspx?&team=support&file=F938262054369625.zipPlease let us know if you have any queries.
Regards,
Poornima