Though the question didn't provide enough, Let me give the general points about those events.
If you look at the order of events the container event KeyDown fires first. Then Cell validating and End Edit if the cell control is in editing mode.
But the key Down of the container won't fire if the cell is in editing mode. Because the event will be captured by the cell and not the gridview.
If you want the gridview capture the specific key events instead of the cell then look at here the workable solution
GridView KeyDown Event Capture;[
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