Hi Ranjan,
Thank you for your interest in Syncfusion products.
Here we have provided a sample as per your need. This sample includes all the implementation of FindAll, Find, Replace, Replace All options for Find and Replace functionality. So that please make use of below sample,
Sample:
http://www.syncfusion.com/downloads/support/directtrac/117881/SampleFindReplace642918408.zip
Please let me know if you have any concerns.
Regards,
Neelakandan