I am working on Radgrid in which i have to make Custom paging like my page size is 20 and record count =5000 so want to to get only 20 records per page. after clicking on pagination number get next 20 Records.
Please have a look at this documentation on Custom Paging , it describes the way to fetch only a fixed number of records and perform operations on this limited set of data. Here is the live example that demonstrates custom paging.