Hello,
You can use client side event KeyDown. Please take a look at the code code below:

<ClientSideEvents KeyDown="Fire" />

<script type="text/javascript">
        function Fire(treeId, keyID) {
            if (keyID == 13) {
                // ENTER
            }
            if (keyID == 40) {
                // Down arrow
            }
            if (keyID == 39) {
                // Right arrow
            }
            if (keyID == 38) {
                // Up arrow
            }
            if (keyID == 37) {
                // Left arrow
            }

        }</script>

Hope this helps.