Thank you for writing.
The internal structure of RadGridView includes a logical (data) and visual (UI) layers. You can read more on that in the following help article - Logical vs. Visual Grid Structure
. The data layer is responsible for all data operations like filtering, sorting, grouping etc. The UI layer is responsible for converting the data from the data layer into a text or another form suitable for visualization. That said when you have a date time column the data behind it would be stored in DateTime instances. These date time instances always stores the milliseconds and therefore will be taken into account by the data layer. You can then apply a FormatString
to the column to not show the milliseconds part and you are good to go.
I hope this will be useful. Should you have further questions, I would be glad to help.