The RadGridView.ValueChanged event is expected to fired when the value in the editor is updated. However, this editor's value is not committed to the cell yet until you press Enter or navigate to another cell.
For the GridViewCheckBoxColumn it is convenient to specify its EditMode property to OnValueChange.Thus, the value will be committed to the associated cell as soon as you toggle the checkbox. In this case, the CellValueChanged event is fired indicating that the cell has a new value. Please give this approach a try and see how it works in your scenario.
I hope this information helps. If you need any further assistance please don't hesitate to contact me.
Dess | Tech Support Engineer, Sr.
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