Check if any object in a 2d array is null

I've got an array var cells = new Cell[w, h], can I loop through all cells without a nested for-loop (I want to check if at least one is null开发者_运维问答)? Ideally I'd want to write something like Debug.Assert(!cells.Contains(null)).

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foreach loop ?

foreach (var item in cells)
{
    //code
}