Please check the online demo Rating / RadRating in RadGrid
. Note that the implemented functionality is similar to the one you want to achieve. The user can rate an item only once then the rating control becomes read-only by setting its property ReadOnly
You can also use the RadRating's client-side event OnClientRating
to cancel the event if a user has already rated. Its functionality is show in the online demo Rating / Client-Side Events
I hope this helps.
the Telerik team
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